>B 608 
.L3 B6 
:opy 1 




Polume XVIII 



May, 1918 



Number 4 



TECHNICAL PUBLICATION NO. 10 



Of- 



THE NEW YORK STATE COLLEGE OF FORESTRY 



AT 



SYRACUSE UNIVERSITY 

I. Notes on Insects Bred from the Bark 
and Wood of the American Larch 

BY 
M. W. BLACKMAN and HARRY H. STAGE 

II. On the Insect Visitors to the Blos- 
soms of Wild Blackberry and Wild 

Spiraea— A Study in Season- 
able Distribution 

BY 
M. W. BLACKMAN 




Published Quarterly by the University 
Syracuse, New York 

Entered at the Postofflce at Syracuse as second-class mall matter 



Volume XVIII 



May, 1918 



Number 4 



TECHNICAL PUBLICATION NO. 10 

OF 

THE'NEW YORK STATE COLLEGE OF FORESTRY 



AT 



SYRACUSE UNIVERSITY 

I. Notes on Insects Bred from the Bark 
and Wood of the American Larch 

BY 
M. W. BLACKMAN and HARRY H. STAGE 

II. On the Insect Visitors to the Blos- 
soms of Wild Blackberry and Wild 

Spiraea —A Study in Season- 
able Distribution 

BY 
M. W. BLACKMAN 




Published Quarterly by the University 
Syracuse, New York 

Entered at the Postoffice at Syracuse as second-class mall matter 



53^0^ 



OF 

THE NEW YORK STATE COLLEGE OF FORESTRY 



To be had upon application by residents of the State 



Technical Publication No. 1, 1914. 

Preliminary Report on the Diseases of Fish in the Adirondacks: 
A Contribution to the Life History of Clinostomun marginatum. 
By Dr. W. M. Smallwood. pp. S-27. 

No. 2, 191G. 

I. A New Species of Pityogenes. By J. M. Swaine. pp. S-10. 
II. Observations on the Life History and Habits of Pityogenes 
hopkinsi Swaine. By Dr. ^I. W. Blackman. pp. 11-G6. 

No. 3, 1916. 

The Development of the Vegetation of New York State. By Dr. 
William L. Bray. pp. 11-186. 

No. 4, 1916. 

The Relation of Mollusks to Fish in Oneida Lake. By Frank C. 
Baker, pp. 15-366. 

No. 5, 1917. 

The Hardwood Distillation Industry in Nev\' York. By Nelson C. 
Brown. 

No. 6, 1917. 

Wood Utilization Directory of New Y''ork. By John Harris, Forest 
Service, revised and rearranged by Nelson C. Brown and Henry 
II. Tryon. 

No. 7, 1917. 

The Relation of Birds to the Western Adirondack Forest. By 
P. ]M. Silloway. 

No. 8, 1917. 

The Black Zones Formed by Wood-destroying Fungi. By Arthur 
S. Rhoads. 

[2] 



LIBRARY OF CONGRESS 

JUN11192t:J 

DOCUV; **ON 



i Insects Bred from American Larch 3 

, No. 9, 1918. 

(^ The Productivity of Invertebrate Fish Food on the Bottom of 

' Oneida Lake, with Special Eeference to Mollusks. By Frank 

^ Collins Baker. 

\J) No. 10, 191S. 

I. Notes on Insects Bred from the Bark and Wood of the American 
Larch. By M. W. Blackman and Harry H. Stage. 

II. On the Insect Visitors to the Blossoms of Wild Blackberry and 
Wild Spiraea: A Study in Seasonal Distribution. By M. W. 
Blackman. 



TRUSTEES 

OF 

THE NEW YORE STATE COLLEGE OF FORESTRY 



Ex Officio 

Dr. James E. Day, Chancellor Syracuse University. 

Dr. John Huston Finley, Commissioner of Edu- 
cation Albany, N". Y. 

Hon. Edward Schoeneck, Lieutenant Governor of 

the Utate Syracuse, N". Y. 

Hon. George D. Pratt, Conservation Commis- 
sioner New York City. 

APrOINTED BY THE GOVERNOR 

Hon, Charles Andrews Syracuse, N. Y. 

Hon. Alexander T. Brown Syracuse, N. Y. 

Hon. John R. Clancy Syracuse, N. Y. 

Hon. Harold D. Cornwall LowTT^ille, N. Y. 

Hon. George W. Driscoll ■ Syracuse, N. Y. 

Hon. Francis Hendricks Syracuse, N. Y. 

Hon. Hendrick S. Holden Syracuse, N. Y. 

Hon. Louts Marshall New York City. 

Mr. Edward H. O'Hara Syracuse, N. Y. 

Officers of the Board 

President Hon. Louis ]\L\rshall. 

Vice-President Hon. John H. Clancy. 

Treasurer Hon. Hendrick S. Holden. 



[4] 



FACULTY 

OP 

THE NEW YORK STATE COLLEGE OF FORESTRY 

AT 

SYRACUSE UNIVERSITY 



JAMES ROSCOE DAY, S. T. D., D. C. L., LL.D., 

Chancellor of the University. 

* HUGH POTTER BAKER, M. F., 1904 (Yale) ; D. Oec, 1910 (Munich), 
Dean of the College; Professor of Silviculture. 

FREDERICK FRANKLIN MOON, B. A., 1901 (Amherst) ; M. F., 1909 

(Yale), 
Professor of Forest Engineering, Acting Dean. 

MAULSBY WILLETT BLACIO^IAN, A. B., 1901; A. M., 1902 (Kan- 
sas); Ph. D., 1905 (Harvard), 
Professor of Forest Entomology. 

EDWARD F. McCarthy, B. S., 1911; M. S. F., 1916 (Michigan), 
Professor of Forest Utilization. 

•NELSON COURTLANDT BROWN, B. A., 1906; LL F., 1908 (Yale), 
Professor of Forest Utilization. 

J. FRED BAKER, B. S., 1902 (Michigan Agricultural) ; M. F., 1905, 

(Yale), 
Director of Forest Investigations. 

LEIGH H. PENNINGTON, A. B., 1907; Ph. D., 1909 (Michigan), 
Professor of Forest Pathology. 

SEWARD D. SMITH, B. S., M. S. F., 1910 (Michigtui), 
Director of State Ranger ScJbool. 

JOHN WALLACE STEPHEN, B. A., 1907; M. S. F., 1909 (Michigan) ; 

M. Pd., 1915 (Michigan Normal College), 

Professor of Silviculture. 

* On leave of absence. 

[5] 



C College of Forestry 

CHARLES CHRISTOPHER ADAMS, B. S., 1896 (Illinois VYesleyan) ; 

M. S., 1899 (Harvard); Ph. D., 1908 (Chicago), 

Professor of Forest Zooloijij. 

HENRY R. FRANCIS, B. S., 1910 (Massachusetts Agricultural College), 
Professor of Landscape Extension. 

SHIRLEY W. ALLEN, B. S., 1910 (Iowa State College), 
Professor of Forest Extension. 

HARRY P. BROWN, A. B., 1909; A. M., 1910; Ph. D., 1914 (Cornell 

University) , 
Professor of Dendrology. 

SOLOMON F. AGREE, B. S., 1896; M. S., 1897 (Texas) ; Ph. D., 1902 

(Chicago) ; F. C. S., 

Professor of Dendrological Chemistrij. 

ROBERT CRAIG, Jr., M. S. F., 1910 (Michigan), 
Professor of Forestry at New York State Ranger Sciiool. 

* REUBEN PARKER PRICHARD, B. S., 1907 (Dartmouth); M. F., 

1909 (Y^ale), 
Assistant Professor of Dendrology. 

LAURIE D. COX, A. B., 1903 (Arcadia College) ; S. B. in Landscape 

Architecture, 1908 (Harvard), 

Assistant Professor of Landscape Engineering. 

HOWARD BLAINE WAHA, B. S., 1909; C. E., 1918 (Pennsylvania 

State College), 

Assistant Professor of Forest Engineering. 

* IIENRY^ HARRINGTON TRYON, A. B., 1912; M. F., 1913 (Harvard), 

Assistant Professor of Forest Utilization. 

ERNEST G. DUDLEY, A. B., 1908 (Leland Stanford Jr. University) ; 

1908-09 (Y^ale Forest School), 

Assistant Professor of Forest Extension. 

ALFRED HUBERT WILLIAM POVAH, A. B., 1912; Ph. D., 1916 

( Michigan ) , 
Assistant Professor of Forest Botany. 

•■' On leave of absence. 



Insects Bred from American Larch 1 

CARL JOHN DRAKE, B. S., B. Fed., 1912 (Baldwin-Wallace) ; A. M., 

1914 (Ohio State University), 

Assistant Professor of Forest Entomology, 

HIRAM LEROY HENDERSON, B. S., 1915 (Michigan), 
Assistant Professor of Forest Utilization. 

* ALAN F. ARNOLD (Harvard) , 
Instructor in Landscape Engineering. 

CARL CHESWELL FORSAITH, A. B., 1913 (Dartmouth) ; A. M., 1914, 

Fh. D., 1917 (Harvard), 

Instructor in Forest Technology. 

HAROLD CAHILL BELYEA, A. B., 1908 (Mt. Allison Univ.) ; M. F., 

1916 (Yale), 
Instructor in Forest Engineering. 

EDGAR C. FEDDIE, B. S., 1917 (New York State College of Forestry), 
Instructor in Landscape Engineering. 

RAYMOND F. HOYLE, B. S., 1917 (New York State College of 

FoDestry ) , 
Instructor in Forest Utilization. 

MERLE R. MEACHAM, B. S., 1913 (Hiram College) ; B. S- in Ch. E., 

1914; Ch. E., 1916 (Purdue University), 

Research Assistant in Dcndrological Chemistry. 

(Fuller Fund) 

ALVIN G. SMITH, B. S., 1915 (New York State College of Forestry), 

Field Assistant in Forest Investigations ; in charge of Syracuse Forest 

Experiment Station at Syracuse. 

*WILFORD E. SANDERSON, B. S., 1917 (New York State College 

of Forestry) , 
Field Assistant in Forest Investigations. 

DON M. BENEDICT, B. S., 1917 (Michigan), 
Laboratory Assistant in Botany. 

C. F. CURTIS RILEY, A. B., 1901 (Doane College) ; B. S., 1905 

Michigan) ; A. M., 1911 (Doane College) ; M. S., 1913 

( University of Illinois ) , 

Special Lecturer in Animal Behavior. 

* On leave of absence. 



College of Forestry 

LILLIAN INI. L-AN"G, 
Secretary to the Dean. 

WALTEE W. CHIPJMAN, B. S., 1893 (Wabash College), 
Cashier. 

ELEANOR CHURCH, B. L. E., 1916 (Syracuse University), 
Lihrarian. 

EDNA E. \^^^ITELEY, B. L. E., 1916 (Syracuse University),. 
Recorder. 



I. NOTES ON INSECTS BRED FROM THE BARK 

AND WOOD OF THE AMERICAN LARCH — 

LARIX LARICINA (Plu Roc.) Koch. 

By 

M. W. Blackman, Ph. D., and Harry H. Stage, M. S. 

[9] 



NOTES ON INSECTS BRED FROM THE BARK 
AND WOOD OF THE AMERICAN LARCH — 
LARIX LARICINA (Du Roc) Koch 

By M. W. Blackman, Ph. D., and Harry H. Stage, M. S. 



Several years ago the senior author was impressed by the 
fact that in comprehensive reports upon forest insects, such 
as those of Packard ('90), Hopkins ('93, '99) and Felt 
('06) a considerable number of boring insects are recorded 
from pine, spruce and several other conifers but only a very 
few are reported from the American larch. For instance, 
Packard ('90) mentions only three borers in larch — Den- 
droctonus sp. (doubtless D. simplex), Hylesinus opaculus 
(probably Polygraphus rufipennis) and T amicus (Ips) pini, 
— although he treats at considerable length thirty-three in- 
sects affecting the trees in other ways. Hopkins ('93) in his 
Catalogue of Forest and Shade Tree Insects of West Virginia 
mentions no insects from larch, while Felt ('06) lists but 
three boring insects from larch — Leptura suh-liamata Rand, 
Tomicus (Ips) pini Say and Tomicus {Ips) caelatus Eich. 
More recent papers by Swaine ('11) and by Hewitt ('12) 
dealing with larch insects list Demlrotonus simplex Lee, 
Ips halsameus Lee, Dryocoetus autographus Ratz., Dryo- 
coetus n. sp. and Ips caelatus Eich. as borers attacking 
recently felled larches or trees weakened by the defoliation 
of the sawfly. 

As it was believed that this paucity of forms known to 
inhabit the bark and wood in the larch was due at least in 
part to lack of study of this tree as a host for boring insects, 
it was decided to take the first opportunity of making such 
a study. Such an opportunity w\as offered when the junior 
author on his return from his home reported the presence 
of many dying and dead larch near Crittenden, Erie county, 

[11] 



12 College of Forestry 

^N". Y. He was persuaded to return immediately and to ship 
to the laboratory a liberal amount of material showing as 
great a variety of conditions as possible. 

On account of the fact that the infested larch was at a 
considerable distance from Syracuse (about one hundred 
and thirty-one miles) the ideal method of procedure in such 
studies — which should consist of field work and insectary 
work so co-ordinated as to check each other and to give the 
best results — were necessarily modified. The field work 
was reduced to a minimum and all field observations were 
made by the junior author at such odd times as opportunity 
offered. However, the work was so planned and conducted 
that the results obtained were in no Avay weakened. In fact, 
in a study of this sort the field work aside from the actual 
collecting of the infested wood, can be dispensed with much 
more readily than the insectary work; which, on the other 
hand, is indispensable because of the impossibility in the 
present state of our knowledge of identifying the immature 
stages of many boring insects. 

The method followed consisted in bringing to the labora- 
tory generous samples of various parts of infested trees. A 
careful and full record of the character and history of each 
lot was kept and each lot was placed in a separate breeding 
cage. The cages were then placed out of doors so that the 
conditions would be normal and as near as possible what 
they Avould have heew if left iii their original location. The 
breeding cage used consists of a strong, well-constructed 
frame of 2 x 2 cypress. The top is covered with fine copper 
wire mesh, while the sides are sheets of glass lowered into 
grooves in the frame. To the bottom of the frame is attached 
a metal flange which may either be fitted into an especially 
constructed base or may be pressed do^vn into the soft earth. 
In most of our work the latter method was used and this 
was true of all of the outdoor breeding work. In these cages 
the sticks were propped up with one end resting upon the 
loose soil or embedded in it, and, except in very dry weather, 
the wood absorbed enough moisture from the loose earth to 
keep it in fit condition for the insects living within. When 



Insects Bred from American Larch 13 

the weather was too dry, water was occasionally sprinkled 
on the pieces of wood to prevent conditions from becoming 
too unfavorable. In any event the conditions were donbtless 
as uniformly favorable as they would have been had the 
material remained undisturbed in its natural environment. 

The various breeding cages were examined daily and all 
insects which had emerged were kept separate with full data. 
As the exact source of each insect emerging was scrupulously 
recorded it was an easy matter later to find the various sorts 
of insects associated in the same pieces of wood and in simi- 
lar wood from other trees or regions of trees. By supple- 
menting such data with later study of the wood it is often 
possible to secure evidence to establish either absolutely or 
pro1)ably that certain insects bear the relation of parasite 
and host to each other. Whenever practicable the exit hole 
made by an emerging insect was found and marked with the 
same lot number as the insect which came from there. Later 
this burrow was opened and the character of the larval mine 
and pupal chambers studied. Specimens of several sorts of 
larvse were also taken at intervals; and, by a later careful 
comparison of such records of adults, burrows and larvse as 
was thus obtained, it was often j)ossible to connect absolutely 
the various stages of the insect and the burrow it produced. 

Description of Woodlot From Which the Larch was 

Secured 

With the exception of five pieces obtained from Wanakena, 
]Sr. Y., all of the infested larch used in this study was secured 
from near Crittenden, I^. Y. Crittenden is twenty-one miles 
east of Buffalo, in the northwestern part of Erie county. 
The woods from which the larch was taken is one of con- 
siderably larger dimensions than is usually met with in that 
section. The tract comprises about one hundred acres. The 
larger part of it is owned by the JSTew York Central Rail- 
road, the rest belonging to the adjoining farms. 

The greater number of tree species in this track belong 
to the climax forest type — the principal ones being hard- 



14: College of Forestry 

maple, beech and hemlock. On the higher areas a few white 
pines are scattered among the hardwoods. Only in two areas 
is the larch to be found. This tract of timber is practically 
in a virgin condition, doubtless owing to the fact that it is 
owned by the railroad. The area has apparently never been 
lumbered and presents fairly good forest conditions — that 
is the general conditions are excellent for tree growth. 

As previously stated the larch is to be found in two 
separated areas, a western grouj) having between thirty and 
fifty trees, and an eastern one of between four and five 
hundred trees. These two areas, which are lower and there- 
fore moister than the- surrounding woods, are about two 
hundred and fifty yards apart and between them is a dense 
undergrowth consisting principally of jioison sumach, willow, 
etc. In these areas, the larch predominates, the total number 
of larch outnumbering all other species of trees combined. 
All sizes of larches are present, from saplings up to trees 
of about 14 inches D. B. II. Reproduction is good although 
of course many of the smaller trees have been killed by 
suppression due to shading. 

A number of the larger larch trees (6 inches D. B. TI. and 
up) have been weakened or killed each year for a number 
of years by the removal of the bark by farmers. A decoction 
made by steeping this bark is thought to make an excellent 
spring tonic for horses and is used by the farmers of this 
locality for that purpose. On all parts of the tract, trees 
may be found from which more or less bark has been stripped 
— these often being completely girdled from the ground up 
to a height of about six feet. Trees completely girdled in 
this way are of course killed immediately while trees stripped 
of their bark on one side only, are not killed outright but 
are greatly weakened. Both dead and weakened trees serve 
as favorable breeding places for many different sorts of 
insects, and it is with insects entering the tree under such 
conditions that we deal with principally in this paper. 

Aside from these trees killed or weakened by the stripping 
off of the bark, the larch trees are under conditions such as 
exist in practically virgin timber. This means that many 



Insects Bred from American Larch 15 

of the trees have reached their maximum growth — have 
become matured — and some such trees are deteriorating 
more or less rapidly. The presence of the excellent breeding 
places offered by the girdled larch had resulted in an increase 
of many insect enemies -^ several of which have increased 
beyond the danger level. These are already successfully 
attacking and killing not only the trees weakened by strip- 
ping off part of the bark but also apparently have in the last 
year or two killed a number of trees which were over-mature 
but were otherwise uninjured. Indeed the conditions here 
are in many respects similar to those reported by Swaine 
('11) in a larch wood near St. Anne's, Que. There several 
trees had been allowed to remain in the forest after felling 
and these had acted as an excellent breeding place for a 
number of scolytid beetles. Several of these were bred up 
to such numbers that they were able to attack and kill the 
living larches remaining. Of the five bark beetles l)reeding 
in this larch, including Dendroctonus simplex, Ips halsameus, 
Ips caelatuSj Dryocoetes autographus and Dryocoetes sp., 
Swaine considers only the first two as serious enemies of the 
larch. 

In the larch woods at Crittenden, the trees which had been 
girdled by farmers in obtaining bark, had acted in much the 
same manner — as incubators for a number of insects breed- 
ing in dying or dead larch. The numbers of several of these 
had increased l)eyond the danger level and they were able to 
attack and kill trees over-mature and deteriorating. Several 
of the trees from which most of the material for this study 
was derived had apparently been killed in this manner. 

In our study Trees I and X, as described later, were trees 
weakened by over-maturing and their death is believed to 
have been caused or at least much hastened by insect work. 
Insects found in l)oth of these trees and in others under 
nearly similar conditions included the scolytids Polygraphus 
rufipennis and Eccoptogaster piceae, the cerambycid Asemum 
moestum, always working very near the base of the tree, and 
the melandryid Serropalpus harbatus. Demlroctonus sim- 
plex was present in the bark of the basal twenty feet of the 



16 College of Forestry 

trunk of Tree I and of others examined in 1015 and 19 17^ 
but no signs of it were to be found in Tree X. There can 
be little doubt that these insects working in the trunk 
together with a number of borers which typically attack the 
branches and the uppermost parts of the trunk such as 
Neoclytus loiigipes^ Leptostylus sex-guttatus, Pogonocherus 
inixtus, and the three species of Clirysohotliris — C. hlanch- 
ardi, C. sex-signata and C. dentipes — greatly hasten the 
death of many weakened trees. Melanopliila fulvoguttata 
and Pliymatodes dhnidiatus are two other borers which are 
often associated with them (the latter only in the lower 
trunk) the first of these being a well-known enemy of weak- 
ened spruces and hemlocks. 

However, in the bit of woodland studied, these insects are 
not working unhampered, but natural forces are at hand 
which to some extent at least are tending toward the re- 
establishment of the normal balance of forces and toward 
the return to a more favorable condition for the larch. The 
work of woodpeckers is much in evidence and seems to be an 
efficient agency in reducing to some extent the numbers of 
the brood of several of the more numerous bark-boring 
insects. The birds seem to work in two ways — first by 
making small conical holes through the bark into the sap- 
wood to obtain the larvse of the larger sj)ecies of beetles 
which have gone there to hibernate or to pupate, and sec- 
ondly by removing practically all of the bark on large areas 
of the trunk to uncover the brood (larvse, pupa and young 
adults) of the bark beetles. 

In some cases this work reached an unusual degree of 
efficiency. Por instance one particular tree forty or fifty 
feet high and about 14 inches in diameter, had had nearly 
all of the bark removed from the ground to the very tip. 
(Figs. 5, 6.) This tree had been heavily infested with 
Dendroctonus simplex, Polygraplius rufipennis and other 
borers, but only a small j)er cent of the original infestation 
had survived the woodpeckers' thorough search for food. Of 
course all of the infested trees had not been so thoroughly 
gone over by the birds and a number of such trees had 



Insects Bred from American Larch 17 

apparently not been found by them at all. However, it is 
safe to say that the woodpeckers were an efficient force, work- 
ing toward the return of the normal balance of nature which 
had been upset by the breeding of certain species of insects 
above the danger level, due to the girdling, season after sea- 
son, of a number of the larches by farmers. It is not believed 
that the woodpeckers will be able unaided to reduce the 
numbers below the danger level, as long as more trees are 
girdled each year, but should this practice cease it is possible 
that they would be able eventually to obtain the upper hand 
and that conditions would return to normal. 

Field Wokk 

The field work consisted in locating the infested trees, 
securing as many species of insects from them in the field 
as possible, noting the condition and probable date of death 
of the host tree, and securing all other data that was thought 
might be of value. The fact that many of the trees had 
been partially stripped of their bark by woodpeckers in 
search of grubs was made use of in readily finding such trees 
under winter conditions. The infested trees were cut down 
and samples of the various parts of the trunk, of the top and 
of the branches were selected. These different lots were 
labeled and shipped to the laboratory where they were placed 
in outdoor breeding cages as recorded previously. 

The larger part of the material was obtained in the field 
April 28 and 29, 19 IG, but from this time till April, 1917, 
as occasion offered smaller lots were added. The material 
placed in breeding cages and from which insects were bred 
out was derived from eleven different trees showing a variety 
of different conditions. Some of these samples were from 
standing trees only recently dead, some from standing trees 
dead 1, 2 or more years and some from trees which had been 
blown over several years. 

In the following pages these various trees are described 
and the insects derived from each are listed. The material 
from the first eight of these trees was shipped from Critten- 



18 College of Forestry 

den April 29, 1916, while the rest was obtaiuecl later, at 
various times, as indicated. 

Tree No. I was a large larch of about 14 inches D. B. H. 
and about 50 feet high. It had probably died late in 1914 
from unknown causes as it had not been stripped of its bark. 
It was the one tree found in the spring of 1916 which con- 
tained living specimens of Dendroctonus svni'plex. The lower 
part apparently had survived longer than the branches as the 
lower trunk was still somewhat sappy. This tree was rather 
interesting from the fact that a large part of the bark from the 
ground to the ti^D had been removed by woodpeckers in search 
of various bark boring insects. Under the portions of bark 
still adhering many sjDecimens of Polygraplius rufipennis 
and Dendroctonus simplex still remained, but it needed only 
a casual examination of the bark to discover that a very 
large percentage had been uncovered and destroyed by the 
birds. 

More material was taken from this tree than from any 
other one source. In one cage was placed the first segment 
of the trunk, the lower end of which was taken from only 6 
inches above ground. The bark on this section was riddled 
by the burrows of D. simplex and P. rufipennis and the sap- 
wood contained many larvae of Asemum moestum. These 
latter were so numerous that just above the root 6 larvae 
were taken from an area of the wood only 6 inches square. 
In addition to these, three other species were bred from this 
section of the tree: the buprested Melanophila fulvoguttata, 
the weevil DryopJithorus americanus, and a small fly Pol- 
lenia rudis. 

In another cage was placed the next section of the trunk 
taken from 18 inches above ground. In the field D. simplex, 
P. rufipennis and the larva of a clerid, apparently Phyllo- 
hcenus dislocatus, and of a cerambycid, Asemum moestum, 
were taken. The adults of all of these and in addition of 
Serropalpus harhatus were bred from this wood. 

In another cage was placed a section of the trunk from 3 
feet above ground, this and the two pieces already described 
having been continuous and forming the base of the tree. 



Insects Bred from American Larch 19 

From it were derived P, rufipennis, D. simplex, several 
specimens of Phyllohaenus dislocatus and two hymenop- 
tereous parasites, — a small undetermined clialcid and Spa- 
ihius tomici, — these being parasitic upon the bark beetles. It 
is worthy of note that A. moestum so numerous in the first 
segment and still present in the second is no longer found 
in this section beginning three feet above ground. 

In another cage was placed a i:)ortion of the trunk taken 
from 30 feet above ground. Burrows and specimens of P. 
rufipennis were quite numerous but none of D. simplex 
occurred this far up. In the breeding cage this section of 
trunk yielded in addition to P. rufipennis, one specimen each 
of the clerid P. dislocatus, the lampyrid Podahrus diadema 
and a small undetermined chalcid. 

Another sample was taken of the trunk at its extreme tip 
about 50 feet above ground. P. ntfipennis was taken from 
this in the field and the engravings were nearly as numerous 
proportionately as in other regions of the trunk (Fig. 2). 
No other insects came from this section of the tree in the 
cages although the bark shows exit holes of both cerambycids 
and buj^restids. These had apparently emerged before the 
sample was placed in the breeding cage, showing that the 
tip of the tree had probably begun to die earlier than the 
lower part — this being in line with the conditions found in 
the lower branches where E. piceae was breeding and in the 
lower trunk which was still sappy in some parts. 

iSTumerous specimens of the limbs of this tree were taken. 
These are from 1 to 2 inches in diameter and are from a 
height of from 18 to 15 feet above ground. The bark upon 
these limbs is thin with only a small scaly and corky layer 
and was apparently quite dry and clung tightly to the wood. 
Some of the burrows in it, however, contained drops of resin 
showing that the bark had been attact while still sappy. 
In the field these samples yielded P. rufipennis and the 
larvae of a clerid, of a buprestid and of a small cerambycid. 
This material was kept out doors in two separate breeding 
cages (there being too much for one) during the summer 
till September 28, and the following insects emerged during 



20 College of Forestry 

that time: P. 7'ufipennis, Eccoptogaster piceae, P. dislo- 
catus, a small moth Epicallima argenticinctella Clem., several 
undetermined psochids, and several parasitic hymenoptera — 
Clieiropaclius sp., Heterospilus sp., SpatJiius tomici, and also- 
another hymenoptera Prosopis sp. 

On September 28 this material was moved into the labora- 
tory, the contents of one cage being placed in tight storage 
boxes while that of the other was left in cages indoors. Dur- 
ing January, February and March of 1917, this material 
both in the breeding cages and storage boxes again became 
active and gave rise to a large number of species not previ- 
ously taken from it. These are the two-year forms and their 
parasites and comprise the following insects: the ceram- 
bycids — PogonocJierus mixtus, Leptostylus sex-guttatus^ 
Neoclytus longipes; the buprestids — Chrysohothris hlanch- 
ardi, G. sex-signata, C. dentipes, Melanophila fulvoguttata, 
and Anthaxia quercata; the hymenopterous parasites — 
PJiasgonophora sp., Odontaulacus hilohatus and Atoreutus 
astigmus; and the small fly — Pollenia rudis. 

Tree jSTo. II was a larch of about 8 inches D. B. II. in 
the west group of trees of this species. It had been killed 
by having the bark removed from near the base in 1914. "No 
insects were taken from this tree in the field, but a segment 
about 20 feet from the base was seen to be infested and this 
was placed in a breeding cage to breed out the inhabitants. 
The insects derived from this material are P. mfipennis^ 
Phyllohaenus dislocatus, the supposedly parasitic fly Mede- 
terus sp. and the siricid Urocerus alhiconiis represented by 
a female and a male. Samples of this one region of this 
tree were the only ones brought from the field. 

Tkee ]^o. Ill was killed by the bark having been peeled 
off of it — probably in 191-4. Above the peeled portions the 
bark was well riddles by the engravings of P. rufipennis and 
also contained the larvae and burrows of several cerambycids, 
of species unknown at the time the material was examined 
in the field. A sample of the trunk of this tree about six 
inches in diameter taken from about five feet above ground 



Insects Bred from American Larch 21 

was placed in a breeding cage and the following specimens 
were bred from it: The cerambjcids Phymafodes dimidiatus 
and Leptostylus sex-guttatus ; the clerids PJiyllohaenus dis- 
locatus and Cymatodera hicolor which were preying upon 
P. Tufipennis principally; six hymenopterous parasites in- 
cluding the two- large pimploid forms Rhyssa Uneolata and 
a new species of Pseudorliyssa, both of them aj^parently para- 
sitic upon Pliymatodes dimidiatus, and four smaller forms; 
three species of Doryctes (all probably new) and Eurytoma 
sp. Of these the three species of Doryctes are probably 
parasitic upon P. dimidiatus and the latter on P. rufi/pennis. 

Tkee ISTo. IV was a tree which was still living but much 
weakened. One of the larger roots which was exposed and 
free of the ground for several inches had been dead about 
two years (killed lOl-t). The bark was rather thick and 
.still adherent, although the wood was beginning to decay. 
Examinations of this root in the field showed the presence 
of adults of a scolytid — Dryocoetes americanus ■ — and the 
larva of a cerambycid which later proved to be Leptura 
vittata. 

This root was removed without felling the tree and was 
■confined in a breeding cage. During the summer two adults 
■of Leptura vittata and two specimens of a small fly — 
Phorhia fuscipes — were taken from this cage. 

This material was left in the breeding cage out of doors 
until November 2, when it was brought in and gone over 
thoroughly. The bark was removed, disclosing the burrows 
and dead adults of Dryocoetus americanus, also a living 
clerid larva of unknown species. Deeper in the wood were 
found the larvae of L^eptura vittata and the adults of the 
small weevils Dryopldhorus americanus. The sample of root 
was placed in a tight storage box, and later gave rise to one 
specimen of L. vittata. This was found dead January 13, 
1917, and the exact date of emergence was unlvnowm. How- 
ever, from the general date of its appearance in the labora- 
tory it would have appeared under natural conditions in May 
or earlv June. 



22 College of Forestry 

Tree No. V had been dead probably three years (since 
1913), Tlie tree was about seven inches D. B. H. The 
lower trunk had been injured upon one side many years 
before (at least ten years), probably by having part of the 
bark removed. However, it had not been entirely girdled 
and the tree had survived. The uninjured bark had partly 
overgro^vn the injury but not entirely — the result being 
that finally the sapwood exposed and all of the heart wood 
was well along in decay. (Figs. 29, 30.) 

Two specimens were taken from the wood of this tree in 
the field — an adult of the elaterid Adelocera hrevicornis 
from the decayed heart wood, and a larva of Serropalpus 
harhatus from the sounder wood. The old burrows of P. 
rufipen7iis were numerous, but no living specimens remained. 

Samples of this tree from two regions were shipped to 
Syracuse and placed in breeding cages. Several segments of 
the trunk from four to ten feet from the base contained con- 
siderable dead sapwood and heart wood well along in decay. 
Another sample from twenty feet above ground contained 
only sound wood. These samples yielded the following 
insects during the summer: The cerambycids Pliymatodes 
dimidiatus and Asemum 7noestum; the melandryid 8erro- 
palpus harhatus, these coming from the more recently killed 
wood; the tenebrionid Tenehrio tenehriodes and the weevil 
Dryoplitliorus americanus coming from the decaying wood. 
In addition two hymenopterous parasites were bred out — the 
large Rhyssa lineolata which is parasitic upon P. dimidiatus 
and a small undetermined chalcid possibly parasitic on 
Dryoplitliorus americanus. 

Tree Xo. VI was killed by peeling probably late in 1913. 
When examined April 29, 1916, in the field it contained no 
living P. rufipennis,, although abandoned burrows of this 
scolytid were very numerous. These abandoned burrows had 
been utilized by the small scolytid Ci^ypturgus atomus, which 
habitually starts its own burrows from those of other bark- 
boring beetles. This one species was the only form taken 
from this tree in the field. When confined in the breeding 
cage samples of this tree taken from one foot above ground 



Insects Bred from American Larch 23^ 

and ten feet above ground yielded numerous specimens of 
Seri'opalpus harhatus and nothing else. 

Tree 'No. VII was one which had been felled by the 
wind about four years previously (1912), but the trunk 
was still free of the ground. The bark was quite loose and 
showed evidence of some decay. Burrows of P. rufipennis 
were numerous, but of course the insects responsible for 
them had long since left this tree. In the field a few larvae- 
of " scavenger beetles," species undetermined, were found, 
and also several larvae of a cerambycid, which was later 
shown to be Monohammus scutellatus. A sample taken from 
the trunk about forty feet from the base (the trunk had, 
however, been recumbent but free of the ground for several 
years) yielded two specimens each of M. scutellatus and 8er- 
ropaljjus ha7'hati(s. Xo other forms were bred from this 
material. 

Tree No. VIII was a small tree about ten feet high and 
having a D. B. H. of two inches. It had been killed by 
shading. No insects were taken from this tree in the field. 
The bark was quite dry and tight and altogether it did not 
form a breeding place which would Ije suitable for many 
wood-boring or bark-boring insects. From the general char- 
acter of the wood and bark one would expect insects to arise 
from it similar to those coming from the limbs of larger 
trees. In fact this expectation was realized when in the 
breeding cage three specimens of Leptostylus sex-guttatus 
and one of Chrysobothris sex-signata appeared. Later 
examination of this stick revealed a few burrows of P. rufi- 
pennis, but these were not normal and in only one or two 
cases were any larval galleries present. 

All of the preceding material was shipped to the labora- 
tory from Crittenden, IST, Y., on April 29, 1916. In addition 
to this, material which was obtained at other times or other 
localities is listed below. 

Tree No. IX was obtained from the College Forest near 
Wanakena, N. Y, This tree of about five inches diameter 



24 College of Forestry 

had been blown down by a lieav;)" windstorm late in May, 
1916. The roots still adhered and the lower part of the tree 
was still alive and green in August. The tree had fallen 
across a trail, however, and the top about five feet from the 
base had been sawed oft" to clear the trail. In August this 
top was found to be heavily infested by Polygraphus rufi- 
pennis and several sections of the trunk from eight to twenty 
feet from the base were shipped to Syracuse and there placed 
in a breeding cage on August 18. During the rest of the 
season the following insects were taken from this cage: 
numerous adults of P. rafipennis, a specimen of a small 
chalcid of undetermined species, Erytoma sp. and Spathius 
tomici. On October 2-1 some of the bark was removed, dis- 
closing numerous young adults of P. riifipennis and also the 
larva of a clerid undetermined and the larva of an unknown 
cerambycid. The material was left, out of doors until early 
in January, 1917, when it was brought into the heated base- 
ment, and later, in Febniary, was transferred to a cool room, 
where it remained till June, when it was again transferred 
to an outdoor breeding cage. On July 3, 11 and 18, speci- 
mens of Neoclytus longipes emerged. All of the evidence 
from other sources goes to show that this cerambycid is one 
which normally requires two years for the completion of its 
life history. It is believed that the normal life history was 
shortened by the treatment the material received. The out- 
door conditions from which it was removed early in January 
corresponded to the first winter, the month in the heated 
basement where the temperature varied from about fifty 
degrees to seventy-five degrees corresponded to the second 
summer and the low temperature in the storage room from 
February to June simulated the second winter. It is worthy 
of note that the specimens of Neoclytus longipes from this 
material are rather undersized although normal in other 
respects. The three specimens in question measure 7, 8 and 
8 mm. respectively, while those from other lots of larch were 
from 9 to 9.5 mm. The length mentioned by Blatchley as 
characteristic of this species is from 9 to 11 mm. 



Insects Bred from American Larch 25- 

During July there was also evidence of the presence of a 
larvae of Monoliaminus, probably M. scuiella.tus, in the con- 
tinued casting out of the coarse " sawdust " characteristic of 
this genus.* 

Tree Xo. X was a large tree about eighteen inches 
D. B. H., which was not observed to be infested with insects 
in April, 1916, when the material from most of the other 
trees was obtained. This tree had not been killed by strip- 
ping of the barL It stood in a rather moist situation in a 
dense part of the wood about fifty feet from Tree I. It had 
died from causes unknown probably late in 1915, or early 
in 1916. When examined in January, 1917, it still con- 
tained the brood of Polygraphus rufipennis and of Eccopto- 
gaster piceae, which must have entered the bark during the 
summer of 1916. The wood was still quite sappy and con- 
tained resin pockets with the contents still unhardened. Also 
the bodies of several adults of E. piceae were found embedded 
by a copious flow of pitch in their e^g galleries showing that 
the tree had been attact while still partly alive. 

A large part of the trunk of this tree from near the ground 
up to the very tip had had much of the bark removed by 
woodpeckers in search of the contained brood. Much of this 
barking had been done quite recently, for when the tree was 
found on January 5, 1917, the fresh chips covered the sur- 
face of the snow. The first samples from this tree were 
taken at this time. These, consisting of strips of the sap- 
wood with adherent bark, were brought in with the hope of 
breeding out specimens of Eccoptogaster piceae, the brood of 
which, together with that of Polygraphus rufipennis^ were 
found in the trunk near the ground. In addition to these 
two scolytids, the larvae of Serropalpus harhatus was also 

* During the winter of 1917-18, this material was examined and 
found to contain living cerambycid larva;. It was stored in a cool 
store room and in the following ^lay and early in June gave rise to a 
number of specimens of Neoclytus longipcs, a single Monohammus 
scutellatios, a single Chrtjsohothris doitipcs, several specimens of 
Xylotreclius undulattis Say and to a mmiber of hymenterais parasites 
which are apparently Odontaulacus hilohatus. X. unchdatus had not 
been previously bred from larch. 



26 College of Forestry 

taken in the field from near the base of the tree. In the 
breeding jar these chips gave rise to specimens of P. rufipen- 
nis, E. piceae, the predator Phyllohaenus dislocatus and the 
parasite Phasgonophora sp. 

On February 26 this tree was felled and samples were 
taken from the trunk at various levels. The first section was 
taken from about eight feet above ground and gave rise to the 
following insects when placed in the breeding cages. The 
two scol^i:ids Poh/grapJius rufipennis and Eccoptogaster piceae 
with the hymenopterous parasites Rhyssa lineolata, Doryctes 
sp. a., Spintherus pulcltripennis, Spathius tomici, Spaihius 
sp., an undetermined pteromalid and the parasitic fly Mede- 
terus sp. ; the predator Phyllohaenus dislocatus^ which preys 
indiscriminately upon all scolytids and upon other small 
bark-boring insects; the cerainbycid Phymatodes dimidiatuSj 
which was parasitized by Doryctes sp. and Rhyssa lineolata; 
the melandryid, Serropalpus harhatus; and the siricids Uro- 
ceiiis alhicornis and Sirex ahhotii. Examination of the base 
of this tree in the field showed numerous larvae of Asemum 
nioestum. 

A second section of the trunk taken about twenty feet from 
the base of the tree yielded exactly the same association of 
insects. A. moestum is of course missing just as at the eight- 
foot level. This form, as we have already seen, is one attack- 
ing only the basal part of the tree trunk and has not been 
found higher than a few feet from the ground. 

The third region of the trunk included all of it above a 
point thirty feet from the ground and consisted of six pieces 
each a little less than two feet long. The insects taken from 
this material included the two scolytids and their jjarasites 
and predators as in the lower trunk, Serropalpus barhatus 
and Urocerus albicornis. 

Tkee ISTo. XI was a small tree of about three inches 
D. B. II. which had been killed several years before (prob- 
ably 1913) by shading. The wood was partly decayed by 
a '' dry rot " and contained numerous specimens of the cur- 
culionid Stenocellis hrevis. The wood was in such condition 
February 26, 1917, that it could be easily pulverized between 



Insects Bred from Ajnerican Larch 27 

the fingers. No other insects were taken from this tree in 
the field and none were bred from it. 

Insect Associations in Larch Wood and Bark 

It is a well-recognized fact that in many cases certain 
species of insects not only live exclusively upon certain 
species of trees, but also that in many cases it is just as true 
that a certain insect is to be found only in a definite region 
of a tree. This, however, by no means holds for all species 
of bark or wood inhabiting insects, for many seem to attack 
indiscriminately any part of the tree from the trunk to 
branches an inch or even less in diameter, just as many insect 
forms attack a large number of tree species with no apparent 
preference. 

There are doubtless several factors which influence the 
choice l)y the insects of certain regions for breeding purposes. 
Perhaps the most important of these is the character of the 
bark, but actual height from the ground is an important 
factor in the case of some insects, especially such as are 
clumsy fliers. 

The character of the bark may apparently influence ovipo- 
sition in several ways. The actual thickness of the bark on 
the lower trunk of large trees undoubtedly deters majiy borers 
from ovipositing on account of the mechanical difficulty or 
even impossibility some find in piercing the thick outer 
layers and placing their eggs where the young on hatching 
will find the proper nourishment. Entirely aside from this 
factor of the thickness of the bark offering mechanical resist- 
ance to the oviposition of certain forms, the bark on the 
trunk has thicker layers of the edible and more or less fibrous 
and spongy inner bark, and this absorbs a greater amount of 
moisture and retains it longer. This maximum of moisture, 
while it offers conditions which are favorable or even neces- 
sary for the proper development of some species of borers, 
is just as truly unfavorable for other species. We shall 
presently see that certain borers are characteristically found 
in the thin-barked tops and limbs which in the next summer 



28 College of Forestry 

after the death of the tree appear to be absolutely dry, but 
which nevertheless apparently offer conditions which are- 
ideal for certain two-year forms. Moisture conditions dur- 
ing the second summer in the trunk and in the thinner barked 
limbs is so extremely different that one would hardly expect 
to find any forms in common between them. As a matter 
of fact this expectation is nearly realized, for of the two-- 
year forms, or of forms occurring under the bark during the- 
second summer after the death of the tree, only two species 
were bred both from the limbs and from the lower or middle* 
trunk. 

Tlie Loiuer Trunk in Dying or Recently Killed Larch Trees.. 
The trunk region itself can be subdivided into two or more 
regions or habitats upon the basis of the insects found, 
therein. In the dying or recently killed trees Dendroctonus 
simplex is perhaps the most characteristic bark beetle inhab- 
itant of the lower trunk. It was not found in the bark at a 
greater distance than twenty feet from the ground and was- 
most numerous in the lower ten feet. In felled trees, how- 
ever, D. simplex occurs throughout the trunk even around 
the bases of the branches. Apparently, then, the limiting 
factor here is distance from the ground, and doubtless the 
clumsy build of the beetle and its rather poor powers of flight 
are responsible. 

Another bark beetle often found in the lower trunk is 
Polygraphus rufipennis. It breeds in all regions of the trunk, 
and even in the tops and larger limbs. It is worthy of note 
that when it occurs in the same tree trunk as D. simplex it 
is much less numerous in the lower regions of the trunk, 
where the latter species occurs, than it is in the middle and" 
upper trunk. This is not true of trees not infested by D. 
simplex. The ex|:)lanation of this seems apparent. The 
Dendroctonus enters the tree slightly earlier than Poly- 
graphus, which on finding the lower truiJv already occupied' 
by numerous broods of the other species, seeks other parts 
of the tree to construct its brood burrows. In trees infested 
by both it is interesting to note that as we go farther and 
farther from the ground the burrows of D. simplex become 



Insects Bred from American Larch 29 

fewer and fewer in number and those of P. rufipennis become 
correspondingly numerous, until at a height of about twenty 
feet D. simplex no longer occurs and P. rafipennis is corre- 
spondingly numerous. 

A somewhat similar condition holds for another bark 
"beetle — Eccoptogaster picew. This scolytid breeds most 
often in the thin-barked tops and limbs of the larch. How- 
ever, sometimes it is also found in the thicker-barked, lower 
trunk, as was the case in Tree X. In this tree it was more 
numerous in the upper tnmk and tops, but some brood bur- 
rows containing living brood were found at a distance of 
only a few feet from the ground, where the inhabitants of 
the'^bark were predominately P. rufi.pennis. 

Still another bark beetle occasionally found in the lower 
trunk of the larch during the first summer after the death 
of the tree is Crypturgus pusillus, although this form is a 
more characteristic resident of the bark during the second 
year. This minute l)eetle seems always to construct its brood- 
burrow as an offshoot from the burrow of some other beetle. 
Usually the burrows so utilized are made by some other 
scolytid — in the larch most commonly by P. rufi-pennis — 
the entrance of this beetle being used in gaining access to the 
inner bark. In other host trees the entrance burrows of other 
scolytids are often utilized and in Ahies balsameus several 
cases have been observed where the tunnels of Monohammus 
scuteUatus had been so invaded, entrance to the burrows 
being gained by way of the " ventilation openings " through 
which the " sawdust " of this sawj^er was cast out. In the 
larch, however, the only species with which Crypturgus has 
been observed to associate itself are P. rufipennis and D. 
simplex. 

Several species of predaceous beetles were found associated 
with these scolytids in the bark. The most common of them 
is the ubiquitous Phyllohaenus dislocatus, which is the most 
common clerid beetle bred from wood infested by bark-boring 
insects in this region. It has been found associated with all 
four species of l)ark beetles mentioned above, and specimens 
of larvae as Avell as adults have been taken from bark infested 



30 College of Forestry 

with Polygraphus rufipennis and Dendroctonus simplex 
especially. The clerid Cymatodera hicolor and the lamperid 
Podabrus diadema were also bred from bark infested with 
P. rufipennis. Both of these are perhaps predaceous, 
although no reference to the food habits of the latter species 
was found in the literature. 

A number of hymenopterous parasites were also bred from 
material containing the brood of these various species of 
scolytids. Of these the most common is Spathius toniici, 
which was constantly associated with P. rufipennis, E. piceae 
and D. simplex. It was especially numerous in Trees I, IX 
and X. Of these Tree IX was from near Wanakena and of 
scolytids contained only the brood of P. rufipennis. Tree X 
contained numerous brood not only of this bark beetle but 
also of E. piceae. Tree I contained all three scolytids and 
all regions of the tree gave rise to specimens of this small 
parasite. There can be no doubt that *S^. toniici is parasitic 
on both P. rufipennis and P. piceae, as different lots of 
material which were j)rftctically pure cultures of either one 
or the other of these species yielded the parasite when placed 
in a breeding jar or cage. We cannot state so definitely that 
D. simplex serves as its host, for the reason that the Dendroc- 
tonus infested material from which the parasite was bred 
contained also the brood galleries of P. i^ufipennis. How- 
ever, it seems very likely that a considerable number of small 
bark beetles may act as host for Spathius toniici. 

Heterospilus sp,, Spathius sp., Spintherus pulchripennis, 
and Cheiropachus sp. were obtained from material contain- 
ing both P. rufipennis and E. piceae, and each may be para- 
sitic upon either one or both of these bark beetles. Eury- 
tonia sp. was bred from material containing the brood of 
P. rufipennis and is j^robably parasitic upon it. Several 
specimens of a small undetermined chalcid were obtained 
from material containing P. rufipennis and D. simplex and 
may be parasitic on either one or both of these or may be a 
hyperparasite upon their parasitic forms. A number of 
specimens of Medeterus sp. were bred from material con- 
taining large numbers of P. rufipennis and some E. piceae. 



Insects Bred from American Larch 31 

M. nigripes Loew. has been previously recorded by Hopkins 
(1899, p. 450) as a parasitic enemy of the larvas of 
P. rufipennis. 

Other boring insects which oviposit in the lower trunk of 
the larch either while it is dying or during the first summer 
after death, include the cerambycids Asemum moestum, 
Monohammus scutellatus, Pliymatodes dimicliatus, and Lep- 
tostylus sex-guttatus; the buprestid Melanophila fulvogut- 
tataj the melandryid Serropalpus harhatus, and the two 
siricids Urocerus alhicornis and Sirex ahhotii. Of these, 
Asemum moestum and Pliymatodes dimidiatus seem to be 
the only forms which were bred exclusively from the lower 
trunk. A. moestum is a sapwood borer and was found only 
in the lowermost few feet of the lower trunk. The eggs are 
often laid in trees which are merely weakened and without 
. a doubt the work of the numerous larvae in the bark and 
sapwood greatly hastens the death of the tree. However, 
oviposition may also occur in recently killed trees, and as the 
insects require at least two years to develop, the adults are 
often bred from trees dead two years or slightly more. 

Phymatodes dimidiatus^ the other cerambycid, which was 
found to breed only in the lower trunk of larch, is more 
typically a dead tree form. Eggs may be laid either in trees 
recently killed or in those dead as much as a year. The life 
history requires a single year for its completion and the 
larvae burrows in the inner bark until it reaches full growth. 
This species may be associated with A. moestum then during 
either the first or second year of the latter's life cycle. 

Monohammus scutellatus, Leptostylus sex-guttatus, and 
Melanophila fulvoguttata are three forms which may breed 
not only in the lower trunk but also in other regions of the 
tree. All three are two-year forms, the larvae of which feed 
in the inner bark and sapwood, and which enter the wood 
only when preparing to hibernate or to pupate. M. scutel- 
latus and M. fulvoguttata are characteristically trunk 
inhabiting forms, but on occasion do breed in the tops or 
limbs of trees. Indeed, more specimens of the latter were 
obtained from limbs than from the trunk. Leptostylus sex- 



32 College of Forestry 

guttatus, on the other hand, most commonly breeds in the 
tops and limbs when it infests larch. There can be little 
doubt that it prefers the thin-barked parts of the tree. 

The melandi-yid Serropalpus harhaius is the wood-boring 
insect most often found in and most characteristic of injured, 
dying, or recently dead larch. It was bred in considerable 
numbers from Trees I, V, VI, VII, and X. The larvae are 
wood-boring insects which live two or possibly more seasons 
in the sapwood or heartwood. This species is found through- 
out the trunk, but is most connnon in the lower trunk below 
the lowest branches. 

The siricids Urocerus alhicornis and Sirex ahbotii occur 
more or less throughout the trunk even up among the 
branches. It is probable that they may even breed occasion- 
ally in the larger branches. However, these forms are all 
typically inhabitants during the larval state, of the wood of 
the part of the trunk free of limbs, as is shown by the fact 
that of twenty-five specimens of the two species bred from 
larch, all but four were from the tree below the level of the 
first still adhering limbs. 

There are several parasites which were bred from wood or 
bark containing one or more or these borers. These include 
Rliyssa lineolata, Pseudorhyssa sp., Odontaumerus cana- 
densis, and three species of Doryctes, all of which are aj)par- 
ently new. These six sj^ecies, four of which are new, were 
derived from three distinct lots of material in three separate 
breeding cages. They Avere associated with P. dhmdiatus, 
M. scutellatus, L. sex-guttatus, A. moestum, 8. harhatus, 
the two predators Phyllabaenus dislocatus and Cymatodera 
hicolor and with Tenehrio tenehi'iodes and DryopMliorus 
americanus (the latter two inhabiting dead and partly 
decayed wood in one of the lots). However, of these numer- 
ous wood and bark-inhabiting forms only tv\^o (P. dimidiatus 
and 8, harhatus) were derived from all three lots, thus estab- 
lishing the probability that one or both of them served as 
hosts for these parasites. 

A later detailed study of nil of the material in these lots 
was made with very interesting results. When the bark was 



Insects Bred from American Larch 33 

carefully removed, bit by bit, forty-five cocoons were exposed 
in one lot consisting of a piece about six inches in diameter 
and two feet long. Nine of these were twelve mm. or more 
in length and all the rest were below ten mm. Several of 
the latter were about nine mm. long and all of the rest smaller 
than 7.5 mm. The smaller ones were found in the burrows 
of P. rufipennis only and were doubtless the cocoons of 
Spathius tomici which had emerged the previous season 
before the material was brought to the laboratory. The 
cocoons of the two larger sizes, however, were found only in 
the burrows of P. dimidiatus, although careful search was 
made in the burrows of other species in both the wood and 
in the bark. The identity of these burrows was absolutely 
established by the finding in several of the pupal chambers of 
dead adults which had never emerged. In the same pupal 
chambers were found the cast larval skins, the mandibles and 
head armature of which are quite characteristic. Close to 
each of the parasitic cocoons, the larval remains of the host 
were found and these on comparison with the larval casts 
found in pupal chambers containing dead adults of P. dimi- 
diatus established absolutely the identity of the parasitized 
form. 

By comparing the sizes of the adult hymenoptera taken 
from this material it was readily established that Rhyssa 
lineolata and Pseudorhyssa sp. come from the larger cocoons 
in the burrows of P. dimidiatus (the cocoons of the two 
being indistinguishable) while the species of Doryctes and 
probably also Odontaumerus canadensis came from the 
cocoons about eight to nine mm. long, found in the burrows 
of the same borer. 

The Upper Trunk in Dying or Recently Killed Larch Trees 
contained the same borers with several exceptions as did the 
lower trunk. Those occurring in this region include the 
scolytids — P. rufipennis and E. piceae and their predators 
— - P. dislocatus and C. hicolor, and parasites ■ — Spathius 
tomici, Spathius sp., Spintherus ptdchripennis, Phasgono- 
phora sp., Cheiropachus sp. and Heterospilus sp. ; the 
2 



^4 College of Forestry 

cerambycid — Monoliartimus scutellatus; the melandryid — 
Serropalpus barbatus; and the two siricids Urocerus albi- 
cornis and Sirex abbotii. There can be no doubt that Lep- 
tostylus sex-guttatus and Melanophila fulvoguttata may also 
breed^ in this upper trunk region, as each of these is found 
both in the lower trunk and in the tops and branches, but 
the limited amount of material confined in our breeding 
cages did not give rise to any. L. sex-guttatus breeds by 
preference in the thin barked tops and limbs and would there- 
fore be more likely to be found in the upper trunk than in 
the lower. M. fulvoguttata on the other hand is more typi- 
cally a trunk-inhabiting form and in spruce and hemlock is 
found throughout the trunk region and only to a lesser extent 
in the tops and limbs. It is likely that its preferences in 
larch would be similar but the small number bred from larch 
does not allow us to draw an adequate conclusion. 

D. simplex, as previously stated, is confined entirely to 
the lower trunk of standing trees, but may breed in the upper 
trunk of felled trees. The limiting factor here is then very 
apparently height from ground rather than the character of 
the bark. The cerambycids Asemum moestum and Phyma- 
todes dimidiatus are two other beetles which have been bred 
only from the lower trunk. Of these the former is practi- 
cally confined to the lowermost part of the trunk and none 
were bred from wood more than three or four feet from the 
ground. P. dimidiaius while not confined to such a limited 
area of the lower trunk was not obtained from wood more 
than ten feet from the ground. 

The Tops and Limbs of Dying or Recently Killed Larch 
Trees. — The tops and limbs of recently killed larch present 
conditions quite different in several respects from those in 
the trunks. In the first place they are inaccessible to a 
number of forms which are clumsy fliers. Aside from this, 
the much thinner bark allows the beetles more ready access 
to the inner bark and sapwood. The inner bark, however, 
neither furnishes so plentiful an amount of food as does the 
thick bark nor does it retain so much moisture. However, 
the thin-barked parts of the tree seem to offer conditions 



Insects Bred from American Larch 35 

which are more suitable for many forms than are to be found 
in other parts of the tree. This is indicated by the fact that 
five species of borers were obtained exclusively from tops 
and limbs while a number of other species taken from other 
regions occur also in the thin-barked parts. Of these latter 
two in particular show a decided preference for the newer 

growths. • 1 1 • 

Most of these forms which characteristically inhabit thm- 
barked regions are species requiring two years for the com- 
pletion of their growth. During the second summer of this 
period the moisture conditions in the thin-barked parts are 
strikingly different from that existing in the thick-barked 
regions. Indeed it is hardly conceivable how the bark or 
sapwood here can be of use as food during times of drought 
when these parts are apparently dessicated, and indeed it 
may well be that during such periods the larva ceases feeding 
and becomes more or less torpid. But however that may be, 
it is a fact that regions showing such conditions are appar- 
ently sought by a considerable number of species in prefer- 
ence to other parts of the tree where moisture conditions^ are 
different. Other factors may enter into this choice and it is 
possible that these may determine the beetle's choice of 
In-eeding places, but our data seem to indicate that this qiies- 
tion of lack of excessive moisture is one of the determining 
factors. This applies not to the forms requiring only a single 
year for their life cycle, but to those which remain under the 
bark for two years. 

A total of ten species of horing beetles were bred from 
thin-barked larch. This includes two scolytids, three ceram- 
bycids and five buprestids. The scolytid most characteristic 
of larch limbs and tops is Eccoptogaster piceae. This seems 
to be its favorite breeding place and study of old engravings 
shows conclusively that there is a larger percentage of larvae 
reaching full growth here than in the trunk region. This 
is especially true of the tops of a diameter of from ll/o to 
31/, inches, although the larger limbs also offer favorable 
conditions. The other scolytid P. rufipennis, v^\\\\e often 
numerous in the tops and occasionally in the limbs is typi- 



36 College of Forestry 

cally a truiLk-inhabiting form and is probably found in tbe 
limbs only wlien crowded out of other regions of the tree or 
when more suitable breeding places are lacking. 

The cerambycids bred from limbs and tops in the order 
of the number of each obtained are Pogonochems mixtus, 
Neoclytus longipes and Leptostylus sex-guttatus. These are 
all three two-year forms. Another species which is almost 
certain to breed in larch tops is Monohammus scvtellatus, 
although none were actually taken. In pine, spruce, and 
balsam this sawyer breeds in all parts of the tree from the 
base to limbs an inch in diameter, and it doubtless will on 
occasion breed in larch lim])s as well as in larch trunks. 

Of the ten borers actually bred from thin-barked larch, 
live are buprestids. These are Melanophila fulvoguttata, 
Anthaxia quercata, Chrysohothris sex-signata, C. dentipes, 
and C. blanchardi. Of these only one species, M. fulvogut- 
tata, was bred from any other region of the tree. All of 
these forms live for two seasons as larvae under the bark, 
but groove both bark and sapwood. They enter the wood 
only to pupate at the completion of their larval growth. 

Associated with these borers are the predator Phyllobae- 
nus dislocatus and various parasites. P. dislocatus doubtless 
invades principally the burrows of the bark beetles P. rufi- 
pennis and E. piceae, but both larvae and adults have been 
found in the burrows of cerambycids and buprestids. The 
23arasites Spathius tomici, Ileterospilus sp., and Cheiro- 
pachus, which are probably parasitic upon one or both of 
these bark beetles were bred from cages containing limbs and 
tops and emerged at approximately the same time as their 
supposed hosts. 

Three other parasites of a somewhat larger size were 
obtained from this material, namely — Odontaulacus bilo- 
hatus Prov., Atoreutus astigmus Ashm., and Phasgonopliora 
sp. These are not only larger in size but also emerged a 
season later than did the bark beetles and the other parasites 
mentioned. Therefore it is believed that these are parasitic 
upon the larger sized species (flatheads and roundheads) 
listed above. It has been impossible to assign these to their 



Insects Bred from American Larch 37 

hosts, even provisionally, as it was not practicable to identify 
the species with the cocoon (their size l)eing so nearly sim- 
ilar) nor was it possible absolutely to identify the burrows 
in which the cocoons occurred owing to some extent to their 
not having been completed by the dying larva. Therefore 
it is not safe to make any more definite statement than 
that cocoons, which from their size were probably those of 
one or more of these forms, were found both in burrows 
which had been made by P. mixtus and also in other burrows 
made by C. hlanchardi. 

Perhaps the most striking difference between the larch 
trunk association and that in the limbs and tops is shown 
when it is stated that the latter includes five buprestids (just 
half of the borers actually taken from thin-barked wood) 
while the trunk association includes but one of this family. 
Thus the buprestids characterize the thin-barked-larch asso- 
ciation and this might well be spoken of as the buprestid or 
flat-headed-borer association. 

All of the borers working in the liml)s and tops are bark- 
borers as distinguished from wood borers. By this it is 
meant that the larvae work in the inner bark and outer sap- 
wood, grooving both with their burrows, although making 
their pupal chamber in the wood. One would expect to find 
in such a location in thin-barked wood eith(n' veiy flat ])orers 
or rather small ones. This perhaps is correlated with the 
fact that such a great per cent of the larvae here are of the 
flathead type and that the remaining forms {P. mixtus, L. 
sex-guttatus and N. longipes) are all (piite small and of 
slender form. 

Decaying Larch. — ^o very thorough data regarding the 
later insect inhabitants of dead larch is at hand, but the few 
observations made should be here recorded. From Tree No. 
IV was obtained a piece of root several inches in diameter 
and a foot or more long. This had been dead several years 
as shown by the fact that the wood had begun to decay. The 
bark, however, was still adherent and had served as the 
breeding place for Dryocoetes americanus, the young adults 
of which were found in the inner bark next to the sapwood. 



38 College of Forestry 

The wood served as a breeding place for the curculionid 
Dryophiliorus a7nericanus, the cerambycid Leptura vittata 
and an unidentified elaterid. The larvae of L. vittata tunnels 
longitudinal burrows in the sapwood and outer heartwood i 
thus hastening decay materijiUy. From the same region of ! 
this i)unky wood adults of DryophtJwrus ainericaiius were 
removed the following fall (I^Tovember 2, 1916). These 
had not appeared in the breeding cages during the summer 
but there was evidence that they had bred in the wood two 
or more generations without change of host. 

Several specimens of the fly Pkorhia fuscipes Lett, were 
also bred from this root. The lai-vse proba])ly lived either 
under the decaying bark or in the punky wood as scavengers 
although they may possil)ly have l)een parasitic upon some 
of the other insect inha])itants. 

Our records [dso furnish data of several other species of 
insects from decaying wood or from wood dead several years. 
Tree V had been partly strip])(>d of its bark several years 
before its death and the exposed wood had never been over- 
grown. This wood was well along in decay and contained 
the burrows of former insect inha})itants, probably Serropal- 
pus harhatus among others. In the field a single adult of 
Adeloccra hrevicorms was taken from this punky wood and 
in the breeding cage it gave rise to adults of the cossoninid 
Dryophthorus americanus and t]ie tenel)rionid, Tenehrio 
tenehriodes. Other specimens of Dryophthorus americanus 
were found under similar conditions in other trees and in 
the same sort of wood numerous specimens of another cos- 
soninid, StenocelUs hrevis, were taken. 

The following tables will show som(>(biiig of the relations 
of these various insects to each other as W(>11 as something 
of their habits and the character of the material in which 
thev breed. 



Eco 



Name oi 

OR P 



Phylloiwiius i 



Ecological Associations op Various 



Predat. 



"RS AND PaSASITES IN LaRCH. 




Pht/llobmiua dialocatus Say. 



DFtirhaclonut eimplex. 
Phymatotlcs ilimidiatus 
Kccoptoijaster ntcea: 
Cjy,itmpn» pmiltus. 
Lejitoatylns gex-mMatus. 
Ncoclylua longinc), 
I oponocherus m ixtus 

ChrmohothnB blanchnrdi, 
Cliiiiaohothris ilcntipea, 

Anthaxitt Quercata 
Scrropalpua iarbatus. 
Snex ahhotii, 
Vrocerus nlhicornis. 



ProEaWy others. 



olor Say. 



Podatrua diadema Pab. 



Rhyaaa Uncolatn Kirby, 



Polvfirnphua niflpcnnis. 
Phymatodea dimidiiitiis 
Leptoatylua aexrjuttatu's. 



Cpiiwtodcrn hirolor 
Podahriia din/If,,,^ ' 



i-yitwioarrn birnlor 
Podahriia dindcma ' 
Spathuia tomici, ' 
neteroapiJtia sp., 
Cheiropachna sn 
Eurytoma sp., 
Ilhyaan Hneolnta, 
Paeudorayaaa sp.. 



noiyrtra .sp.. n, b, 
Paeudorhiissn sp 
Pttrytotnu sp.. 
llbysaa lincolatd. 




Phymatodea dimidinl 
Leptoatylua aex-mttc 
Aaemum moeatum, 
Serropalpua harbatua 
Vrocerua albteoniia, 
Sirex ttbbotii, 
Polypraphna ru/lpenn 
Eccoptoffaater picew. 



Phymatodea dimidialus 
Leptoatylua aex-outtntua. 
Serropatpua bartatua, 
Polyoraphua ruflpennia 



Phymatodea dimidiat 



Phymatodea dimidiatua. 




Odontaulaeua bilobatua Trov. 



Metanophija )ulio,i,dtata. 
Chryaobothi is btamhardt, 
Chryaobothria srx-aUinata 
Chryaobothria dnitiiies ' 
Anthaxia quereata 
Pogonochenia mixtua 
Neoclytua toui/ipes 
Leptoatylua Bc.r';uttat 
Polyriraphua runpennh 
Eccoptooaatei- 

Same a.s above : also 
Dendroetonua aimplcx, 
Phymatodea dimidiatua 
Serropatpua barbatua, 
Urocenia albicomia, 
oirex abbotii. 



PhyUohacmia dialoeatua 
Cvma odera bieolor. 
Paeudorhyana sp 
Doryetea sp., a i> c 
Eurytoma sp., ' ' 
Spathlua tomiel. 
Spathiua sp. 

Pteromalid (undetcTininpil), 
Medeterua sp. ' 



• above excoi>t the last 



Chryaobothria lilanclmrdi, 
Melauophlta /ulicinuttata, 
Pogonoeherua mixtua. 



Phyllohaem 
Phaaoonoph 
Cheiropaetn 
Atoreutiia aetif, 
tteteroapilus si 
Krtathiua toinie 
Pollenia rudia. 



sp.. 



Spathiua sp. 



Doryetea sp., a, b, c, 



Hetcroapiiua sp. 



Atoreutua aatigmua Ashm, 
Spintherua pulchripennia Cwfd, 
Eurytoma ap. 



Polygraphua rufipeunia 
Eecoptopaater pieew, 
Phymatodea dimidiatua 
Serropatpua barbatua, ' 
Vrocerua alMcornia 
Sirex abbotii. 



Phymatodea dimidiatua 
Leptoatylua aex-guttatua, 
Polyoraphua ruflpennia, 
„ (S|).a, abso with 
Lceoptoffaeter picew 
Serropalpua barbatua, 
TJroeerua albicomia 
Sirex abbotii). 



I Phyllohaeuua dialoeatua, 
. Cymatodera bieolor, 
I Rhyaaa Uueolata, 
, Paeudorhysaa sp., 
[ Eurytoma sp.. 
I (,Sp.a also with 

Spintherua pulchripennia, 

Spathiua sp. and 

Medeterua sp.}. 



Same as for Spathiua sp. 



Poluarapliua ruflpennia, 
phymatodea dimidiatua, 
v.'i'?'!"'"'. 'ex-puttatua, 
Deoclytua longipea. 



Same as for O. bilobatua 



(Jhryaobothria blanrhardi, Same as for 0. bilobatua 

Porjonocherua m&tua. above. 



Polygraphua ruflpennia, 
Eccoptoyaater pjocir. 



for Spathiua sp. 



Polyoraphua ruflpennia. 



Phyllobaenua dialocatu 
Cymatodera bieolor, 
Riiyaaa tincolata, 
Paeudorhyaaa sp., 
Doryetea sp., a, b, c. 




EcoLooioAi Eelations and Associations of the Vabiods Boee 




Insects Bred from American Larch 39 

DISCUSSION OF SPECIES 

In the following pages each of the species of insects bred 
from larch are discussed in some detail. In writing this 
discussion all of the material upon the habits and biology of 
each species which was available has been read and much 
of it incorporated. In addition considerable new material 
in the way of biological notes will also here be found, in 
fact, for a number of species practically all of the account 
here given is new and in all except a few cases much of it 
is new. 

I. Dendroctonus simplex Lee. 

Dendroctonus simplex is distributed throughout the north- 
eastern part of the United States and eastern part of Canada 
apparently occupying the same range as its host plant, the 
eastern or American larch. Its most southern range is 
reported by Hopkins ('98, p. 343), who has taken it from 
West Virginia. lie also ('09, p. 120) records it from sev- 
eral localities in Michigan, Maine, New Hampshire and 
Canada. Swaine (1910 a, p. 81) also reports having seen 
specimens of this species from Mackinac, Man., and (1909, 
p. 99) records it from Colorado, California and New 
Mexico. That the record for the latter three localities is a 
mistake is claimed by Hopkins ('09, p. 118). 

This species apparently confines its attacks to the Ameri- 
can larch Larix laricina, Hopkins ('09, p. 120) although 
Swaine ('09, p. 99) gives Larix and Picea as hosts. 

Dendroctonus simplex attacks injured, dying and felled 
trees, excavating long, slightly winding egg galleries in the 
inner bark which slightly groove the surface of the wood. 
The eggs are placed in groups of three to six or more, alter- 
nately along the sides of the galleries (Fig. 1). The larval 
galleries are short and extend out perpendicularly from the 
main egg gallery. According to Hopkins ('09a, p. 104) 
" The broods occupy the bark of stumps and logs and the 
trunks of standing trees from the ground to the branches 
or on into the tops. Fresh attacks on living trees cause a 
flow of resin or red boring dust in the loose bark and around 



40 College of Forestry 

the base of the trees. This species is capable of extensive 
depredations on the largest and best larch, but apparently 
prefers to infest injured, dying and felled trees." 

The winter is passed principally in the adult stage, within 
the inner bark of trees and stumps in which the larvae have 
spent the preceding summer. Activity begins with the first 
warm weather in the spring. There is apparently but one 
generation annually, although under certain circumstances 
there may be at least a partial second generation. The larvse 
of the first generation begin to transform to the adult stage 
at Crittenden during August, and by the first of September 
practically all the brood are callow adults. 

In our work this species was taken during three successive 
seasons but in each year was found only in one tree. In the 
springs of 1915 and 1916 the wintered-over brood was found 
under the bark of the lower part of the trunk associated with 
Polygraphus rufipennis. 'No pitch tubes were seen and while 
the egg galleries in many cases did contain some pitch, there 
was not evidence of a copious flow of the material. In mid- 
summer, 1917 (July 24), a large larch tree was observed 
which had numerous streams of pitch from one to seven 
inches long rumiing down the bark. No pitch tubes were 
present but this material came from recently made burrows 
of D. simplex. On examining the inner bark, many dead 
bodies of the adults were found embedded in the pitch which 
completely filled many of the egg galleries. Other egg gal- 
leries had been kept free of pitch by the work of the adults. 
The larvae were nearly full grown but no pupae were observed. 

This tree was about one foot in diameter, A strip of bark 
about ten inches wide and five feet long had been removed 
from one side. The tree was still quite green but had made 
practically no growth during the season. The streams of 
pitch were present upon the bark from the base to a height 
of about fifteen feet. A few — but only a few — burrows 
of Polygraphus rufipennis were found on this tree but the 
attack of this insect seemed to have been unsuccessful on 
account of their inability to combat the excessive flow of 
resin. In Tree No. I also P. rufipennis was found associated 



Insects Bred from American Larch 41 

with D. simplex near its base, but as the P. rufipennis became 
more numerous farther from the base the D. simplex became 
less abundant and above twenty feet none were to be found. 
In this tree no pitch tubes were present showing that the 
tree was either dead or in a very weakened condition at the 
time of the entrance of the beetles. 

Adults of D. simplex were taken from their burrows in 
the field on April 5 and April 22. They were taken from 
the breeding cages under natural conditions on May 25 and 
26. Swaine records (1910, p. 81) finding the egg-tminels 
containing eggs in the outer ends and larvae of all sizes 
boring in the bark on July 10. On August 6 these tunnels 
were occupied by grown larvse. Pupse, recently transformed 
adults as well as emergence holes were present. Eggs of a 
second brood were found as late as August 26. This varia- 
tion in life history is no more than should be expected. No 
dogmatic statements concerning the seasonal histoiy of an 
insect can safely be made, for life cycles are more subject 
to variation than are structural details. It would seem to 
be axiomatic that a physiological process should be more 
readily altered by unusual environmental influences than 
would be anatomical structure, yet some of our entomologists 
speak of the seasonal histories of insects as if they were 
immutable. 

D. simplex is usually not preceded in larch by any other 
insect but in some cases may be. Trees injured by blaze 
scars or by abrasions often attract Serropalpus harhatus. 
Diseased or weakened trees also may be infested by Asemura 
Dwestum or Melanophila fulvogutta even before the entrance 
of the brood of D. siinplex. As we have already seen P. 
rufipennis is a bark beetle often associated with D. simplex 
in the bark. 

The predator Phyllohaenus dislocatus is often found not 
only in the burrows but also is frequently seen actively 
scurrying over the bark of infested trees. Spathius tomici 
and an undetermined chalcid have been bred from material 
containing both D. simplex and P. rufipennis. The former 
of these is certainly parasitic upon P. rufipennis and may 
well parasitize D, simplex also. 



42 College of Forestry 

Polygraphus rufipennis Kirby 

Polygraplius rufipennis has a wide range throughout the 
greater part of the United States and Canada. It has been 
recorded from Alaska, from many regions of Canada and 
from throughout the northern and eastern United States, 
extending as far south as Georgia and Louisiana (Hamilton, 
1894, p. 35) ; Packard (1890, p. 721) reports it from Colo- 
rado and from Tacoma, Washington ; and Fall and Cockerell 
(1907, p. 217) have found it in ^^ew Mexico. Correlated 
with its wide distribution, P. rufipennis breeds in a variety 
of host trees. Packard (1890, p. 722) records it from white 
pine and Rocky Mountain pines and spruces, Hopkins (1899, 
p. 249) reports it in spruce, larch and scrub pine and Felt 
(1906, p. 386) has found it associated with Dryocoetes sp. 
in spruce and with Pityogenes punctipennis (" Tomicus hal- 
sameus ") in balsam. The senior author has numerous 
specimens of this insect from red spruce (Picea rubens) 
associated with two species of Dryocoetes, Pityogenes puncti- 
pennis, Ips caelatus. Crypturgus pusillus and other forms 
and has also taken it from stumps of white pine in company 
with the latter two species. In the Northeastern United 
States the red spruce is the favorite host tree. 

Dr. Hopkins (1899, pp. 246-251) has given us the fullest 
and one of the earliest accounts of the biology of this insect. 
He says : " The adults emerge in May and June, and are 
attracted to the stumps, trunks and tops of recently felled 
trees and such trees as are weakened in vitality from the 
attack of insects like that of the destructive pine bark beetle 
[Dendroctonus frontalis^ , diseases or any other cause. They 
then commence to excavate their entrance galleries through 
the outer bark . , , , This entrance burrow is extended 
to the outer surface of the inner soft bark, where a broad 
cavity is excavated which is utilized as a nuptial chamber. 
In the meantime the female which appears to do the greater 
part of the first excavating, is joined by a male which stations 
himself in the entrance gallery to keep out enemies and 
objectionable visitors [doubtless also other males], and to 
render assistance in expelling the borings. The female then 



Insects Bred from American Larch 43 

excavates a gallery from oue edge of the nuptial chamber 
through the inuer bark to the wood, thence through the inner 
layer of bark, usually at right angles to the bark fibers, for 
a distance of one or two inches. Along the sides of this 
so-called brood or egg-gallery, she deposits her minute, pearly 
white eggs in a succession of small notches. By the time the 
first female has her egg-gallery fairly started, one to three 
other females are admitted, and each excavates a similar egg- 
gallery in different directions from the nuptial chamber. 
Before all of the galleries are finished, the first eggs com- 
mence to hatch into minute white grubs, which burrow 
through the inner bark, on which they feed. By the time all 
the eggs have hatched, the surrounding bark is filled with 
these grubs of various ages and sizes, and soon, all of the 
bark from the inner to the outer layer, for a radius of two 
to four inches, is completely perforated with their irregular 
burrows. In the meantime, the male guards the entrance 
and the females either rest in the nuptial chamber or egg- 
galleries or emerge to enter the bark in another place to start 
a new brood. When the grubs and larvse have attained their 
full growth, they excavate a broader cavity at the end of their 
burrow or mine, in which they change to the puj^aB stage, 
thence to the adult and either emerge from the bark and 
start a second brood, or remain until the following spring. 
Probably two or three broods may occur in one season, com- 
mencing with the first eggs deposited in the spring, but my 
observations lead me to believe that owing to the shortness 
o:£ithe season at the high elevations occupied by the sj^ruce 
of this State [West Virginia] there is generally but one 
brood." 

But little can be added to the observations upon the phases 
of the activity of F. rufipennis covered in the above account. 
However, observations upon the behavior both of this species 
and of other species of polygamous beetles leads us to doubt 
very much if the female ever normally starts the excavation 
of a brood burrow. In all cases, observed by the senior 
author where the burrow was started by a female the excava- 
tion was continued as a simple gallery with no sign of a 



^^ College of Forestry 

nuptial chamber. In most cases such burrows were for feed- 
ing purposes only, with not only the nuptial chamber lacking 
but also with the egg niches omitted. In a few cases where 
the lemale operating had been removed from a burrow 
already occupied by a male and several females she con- 
structed egg niches in the side of the independent burrow 
and deposited eggs therein, but made nothing resembling 
either a nuptial chamber or a nuptial recess. In fact in 
such burrows it was necessary for her to back out at the 
entrance in order to turn around, no place in the gallery 
being wide enough for this manoeuver. 

Some interesting observations have been made upon the 
proportion of the sexes as they occur in their burrows in 
birch and the bearing of this upon fecundity. This work 
is based on a careful study of fifty engravings and burrows 
— all the uninjured ones available in the material at hand. 
Had more engravings in larch been available they would 
have been used, although it is believed that a studv of a 
greater number would not have materially changed the 
general results. 

The following tables based on the study of fifty engravings 
are self-explanatory: 

Number of engravings having one-egg gallery 6 

Number of engravings having two-egg galleries '.'.'.'.'. oo 

^umber of engravings having three-egg galleries . ' 14 

Number of engravings having four-egg galleries ... 6 

Number of engravings having five-egg galleries ............ 2 

Total number of egg galleries studied j^ 

Minimum length of egg gallery 4 ^^^ 

Maximimi length of egg gallery .' .' ; ; ." gO mm' 

Average ength of egg gallery ; ; 24 55 mm" 

Average length of egg gallery in uniramous tvpe *34' mm* 

Average length of egg gallery in biramous tvpe 26 3G mm" 

Average length of egg gallery in triramous type 22 38 mm" 

Average length of egg gallery in quadriramous tvpe. ... 26' 37 mm" 

Average length of egg gallery in guinquiramous type. . .. 18 mm." 

* In one case the single egg gallery measured 60 nun. in length which 
m so small a number would unduly raise the average. If this case is 
lett out ot consideration the average length would be 28.8. 



Insects Bred from American Larch 

Minimum iuiml>er of egg niches in egg gallery 1 

Maximimi number of egg niches in egg gallery &^ 

Average number of egg niches in egg gallery. . ^^'-^^ 

Average number of egg niches in uniramous gallery ^J.4 

Average number of egg niches in biramous gallery /5.^0 

Average number of egg niches in triramous gallery 1S.5- 

Average number of egg niches in quadriramous gallery... Ib.lU 

Average number of egg niches in quinquiramous gallery.. 14. o 



45 



It would seem from the above that each female produces 
a larger number of eggs when her mate serves no other 
females, i. e., under conditions of monogamy. However, in 
order to get at what might be styled the individual efficiency 
the total number of eggs in all the egg-galleries of the burrow 
should be divided by the total number of individuals (male 
and females) in the burrow. The following results then 

appear : ^ 

'- ^ Eggs per 

Number of eggs Male Females Individual 

29.4 - (1 + 1) = 14.7 
50.72 - (1 + 2) = 6.91 
55.56 -^ (1 4- 3) = 3.89 
64.40 -^ (1 + 4) = 12.88 

71.5 -- (1 + 5) = 11.91 

Thus the following facts appear: The greater the number 
of females in a burrow, the greater is the total average num- 
ber of eggs per burrow but the less per individual female. 
Under average conditions the males outnumber the females in 
the ratio of two and one-half to one and the greatest reproduc- 
tive efficiency is shown in burrows containing one male and 
two females." Should the sexes occur in nature in equal num- 
bers the greatest efficiency would be shown in burrows having 
one of each sex, for then each female on an average would 
deposit 29.4 eggs although the individual efficiency is only 
half that amount; while in a biramous burrow each female 
lays, on an average, 25.36 eggs, but the individual reproduc- 
tive' power is greater than in the former case. However, if 
in nature the females should outnumber the males at the 
ratio of four to one or five to one the greatest number of 
eggs would be produced by their breeding in the same ratio. 



4() College of Forestry 

It is perhaps worthy of remark that in engravings of P. 
rufipennis in spruce observed both in the Adirondacks and 
Catskills there is a greater preponderance of females than 
in the larch material from Crittenden, The exact signifi- 
cance of this can only be guessed at, but to one who has for 
a numl)er of years spent several weeks in each of these 
regions at the season of the year when the greater number 
of these insects are establishing themselves in their new 
breeding quarters, an explanation which has occurred to the 
senior author may appeal with some force. The young adults 
are leaving their old hosts and entering new ones during the 
early and middle parts of June when violent rains are a 
nearly daily occurrence. It is the male which first leaves 
the old host and which makes the entrance burrow and 
prepares the nuptial chamber in the new host, while the 
female does not emerge from the old host until several days 
later. During the early construction of the new burrow the 
males are exposed to various dangers, and to one who knows 
in general the habits of bark beetles it is very apparent that 
in a rijiny season, many lose their lives by the very frequent 
and violent rain storms. On the other hand the females, 
leaving the protection of the old host later, are not subject 
to so many dangers as a large percentage of them find nup- 
tial chambers already prepared for their reception. 

Thus if the sexes occur in about equal proportions in the 
old host as has been shown to be the case in Pityogenes hop- 
kinsi, Swaine (Blackman, 1915), the preponderance of 
females over males in the new brood chambers would vary 
with the occurrence of storms at the time of transferring 
from old to new host. It is believed that the more equable 
climate in Erie county, JST. Y., from which region the 
infested larch was obtained had allowed a larger number of 
males to establish their new breeding quarters than is usually 
j)Ossible in the Adirondacks and Catskills where violent 
storms are of nearly daily occurrence. 

Hopkins (1899, p. 248) has said that: "Probably two 
or three broods may occur in one season — but my observa- 
tions lead me to believe that . . . there is generally but 



Insects Bred from American Larch 47 

one brood." We agree thoroughly with this statement. In 
New York it is within the possibilities for two or even two 
and a half generations to occur in one season but under field 
conditions it is doubtful if this possibility is ever realized. ' 
It is certain that a single generation is the rule and that 
occasionally a partial second generation is to be found — 
this second generation wintering over as partly grown larvae. 
In larch, adults have been taken from under the bark on 
February 9, 29, April 22, 29, and October 24, and have been 
bred out in cages throughout the latter part of May and the 
early part of J une. Larvse were obtained from beneath bark 
April 22, 29, and October 24. In the Adirondacks the eggs 
of the main generation which has wintered over in the adult 
stage are laid througkout June, the exact date at which 
laying begins being of course dependent upon the season and 
varying from year to year. 

P. rufipennis is associated with a great variety of other 
insects, borers, predators and parasites — the actual rela- 
tions sometimes being quite close while in other cases they 
are quite remote. The scolytids Dendroctonus simplex, 
Eccoptogaster picece, the cerambycid, Phymatodes dimidia- 
tus. and the two siricids, Urocerus alhicomis and Sirex 
abotii are often associated with P. rufipennis throughout 
their life history. Of these the four beetles are inhabitants 
of the bark and therefore are influenced by each other much 
more than they are by the siricids which spend their larval 
life in the wood entirely. In general perhaps, each of these 
bark-inhabiting species is influenced adversely in that their 
food is limited by the presence of the other. However, under 
some conditions the association may be of mutual advantage. 
For instance it is apparently true that P. rufipennis is ordi- 
narily unable to breed to advantage in a living tree yet when 
such a tree is attacked simultaneously by D. simplex, P. 
nifipennis and E. picece, or by the first two of these, its 
resistance is more readily overcome and it not only serves 
as a more favorable breeding place for these forms but for 
others as well. It is believed the D. simplex is able to kill 
weakened larch unaided but no cases were observed where it 



48 College of Forestry 

had attacked living trees unaccompanied by the ubiquitous 
P. rufipennis. 

The rehitions of this bark beetle with the various species 
requiring two years for their life cycle is complicated by the 
fact that the association may be with either the first or the 
second year of the life of these beetles. Our data shows that 
the cerambycid Asenium moestum and the melandryid >S'er- 
ropalpus harbatus may be associated with Polygraphus 
during either the first or second year of their life history. 
In other words either of these forms may enter the tree at 
least a year earlier than P. rufipennis or may enter during 
the same season. Neither of these would afi^ect the bark 
beetle directly as they are both wood borers throughout their 
larval life. Those which j^recede it would aid in weakening 
the resistance of the living tree, thus making it a more suit- 
able host for various bark beetles, while those which enter 
at the same time would have little or no either direct or 
indirect effect. 

The large majority of two-year forms, however, enter the 
larch during the same season as P. rufipennis. This list 
includes the cerambycids — Monohammus scutellatus, Lep- 
tostylus sex-guttatus,, Pogonocherus mixtus, Ncoclytus long- 
ipes; and the buprestids, Melanophila fulvoguttata, Chryso- 
hothris dentipes, C. sex-signata, C. blanchardi and Anthaxia 
quercata. All of these feed under the bark and therefore act 
the role of rol)bers by eating the inner bark before the smaller 
bark-beetle larvae can complete their growth. In some cases 
also they may kill the smaller brood outright (Hopkins, 
1899, p. 410) when they by chance meet them under the 
bark. 

The associated predators and parasites are mentioned in 
another connection and it will suffice to say here that the 
predators include Phyllohaenus dislocatus, which appears to 
be ever present in infested larch, Cyniatodera hicolor, and 
Podahrus diadema. The parasites include Spatliius toniici, 
Spathius sp., Heterospilus sp., Cheiropachus sp., Eurytonia 
sp., Spintherus pulchripennis, a small undetermined ptero- 
malid and the parasitic fly Medeten^s sp. 



Insects Bred from Americayi Larch 49 

Eccoptogaster piceae Swaiiie 

Eccoptogaster yicece has been previously recorded from 
only two localities — Hudson, Quebec (Swaine, 1910, p. 33), 
and from Steuben county, Ind. (Blatcbley and Leng, 1916, 
p. 589). Swaine obtained his specimens from the brood 
burrows in the branches of white spruce (Picea canadensis) 
while Blatchley and Leng record it from tamarack (Larix 
lariciTm) /' 

Swaine (1910) accompanies his original description of 
this insect with notes upon its habits and descriptions of its 
engravings. Full grown larvse and pupae were abundant in 
the latter part of May and the adults began emerging in the 
laboratory June 6 and egg-laying began early in July. 
Regarding the burrows he says: " The egg-tunnels deeply 
score the wood lengthwise of the grain. The tunnels are 
divided into two portions by a nuptial cluimber, situated 
usually near the middle, and from the nuptial chamber a 
short, oblique tunnel leads to the entrance-hole above. From 
ten to thirty eggs are laid in shallow nitches along each side 
of the tunnel, and well packed in with fine bits of wood. 
The larval galleries arise from the tunnels in a fairly regular 
manner, but soon through their windings cross each other 
in every direction, but still show a general tendency to follow 
the grain of the wood, which they deeply score." 

Our study of a large number of engravings of E. picew 
bring out some additional facts. In the first place, the egg- 
galleries in larch at least are normally not only considerably 
longer than those figured by Swaine but also contain a con- 
siderably larger number of egg-niches as will be readily seen 
by referring to the tabulated data given later. In a study 
of the engravings certain facts appear at first sight. The 
number of egg-galleries in a single burrow varies from one 
to three, by far the greater number of engravings having 
two egg-galleries (Fig. 7). This means, doubtless, that 

* Engravings which were undoubtedly made by this species have been 
observed by the senior author in Picea rubens in the region of Cranberry 
Lake, but specimens of the beetles have never been obtained from this 
host. 



50 College of Forestry 

normally two females and one male occur in a brood burrow. 
The beetles breed by preference in tops, i. e., in the upper 
part of the trunk among the limbs where the bark is thin 
but they may occur anywhere in the trunk or limbs. When 
in the trunk, the entrance gallery leads from the outside 
obliquely upwards through the bark to the nuptial chamber 
which is excavated nearly entirely from the sapwood. This 
is usually roughly triangular in shape with one of the angles 
continuous with the entrance and the other two above. 

The first egg-gallery constructed is apparently invariably 
upward, proceeding with the grain of the wood from one of 
the upper angles of the nuptial chamber (Figs. 9, 10). The 
second egg-gallery starts from the other upper angle, but 
immediately turns downward and as soon as it clears the 
nuptial chamber proceeds nearly, but usually not exactly 
parallel with the grain of the wood in a direction opposite 
the first gallery (Figs. 7, 8). When a third gallery is present 
it arises from the side of the nuptial chamber opposite to the 
second, turns outward and downward nearly with the grain 
of the wood but diverging slightly (Figs. 7, 9). 

It is interesting to note that the upper egg-gallery, i. e., the 
one first constructed, is longer (or longest) in sixty per cent 
of burrows having two or three galleries. In seventy-three 
per cent the upper gallery contains the larger number of 
egg-niches, showing a greater fecundity of the female first 
fertilized over those fertilized later. This data is based on 
careful measurements and counts of one hundred brood bur- 
rows. Further study shows that the average length of the 
first (upper) egg-galleries is 30.3-i m. m. and of the latter 
ones is 23.67 m. m. ; the average number of egg niches in 
the first egg-galleries is 38.12 and of the lower only 24.75. 

In gathering this data burrows having three galleries were 
used as well as those having two, and in the former cases 
both lower galleries were included. It might be objected 
that this would seem unfair as one of the three is so likely 
to be abnormal, it being logical that if the second contains 
fewer eggs than the first, the third would contain fewer than 
the second. There being no way to determine which of the 



Insects Bred from American Larch 51 

lower galleries was first constructed, the upper gallery was 
compared in fourteen engravings with the lower gallery hav- 
ing the most egg-niches. The average for the upper gallery 
is 33.64 eggs and for the lower gallery 29.07 eggs. Of the 
fourteen burrows the greater number of eggs is found in the 
uj)per gallery in eight cases, in one of the lower ones in five 
cases, and one case shows the two equal. 

The eggs are laid in May and June and the beetles prefer 
dying or very recently dead trees in which to breed. They 
often, however, breed in bark which is still quite snppy, and 
cases have been found where the excessive flow of pitch in 
the egg-gallery has caused the gallery to be abandoned. Other 
cases are numerous where a considerable amount of pitch 
had exuded into the egg-gallery but where the beetle had been 
able to overcome the resistance of the tree and to rear its 
brood. 

An attempt was made to induce reared material to re-enter 
larch anew in order that their habits and life history could 
be studied more in detail. Material containing the brood of 
E. picece was brought into the laboratory on January 5 and 
February 26, 1917. The larvae, which were in various 
stages from half-grown to nearly full-sized larvae, readily 
transformed and emerged in large numbers as adults. Larvae 
which were observed to be full-grown and ready to pupate 
were removed from the bark and placed in slender dishes 
upon slightly moistened sawdust. A number of these 
pupated and transformed to adults while under observation. 
Full notes were taken of all observations. The length of the 
pupal stage under laboratory conditions was found to be 
about nine to eleven days. Extracts from the notes on one 
individual are given below. 

A larva pupated May 20. During its pupal stage it 
showed little activity, practically the only movement being a 
wriggling motion of the abdomen. This pupa transformed 
into the adult stage at 8:45 a. m. on May 31. The newly 
emerged adult showed considerable motion of the head and 
legs and contraction and expansion of the alxlomen. It 
would seem to contract as much as possible with head bent 



52 College of Forestry 

downward and then thrust out its abdomen, head and legs 
in a " stretching " movement. The true wings were extended 
at full length and the elytra were in a nearly normal posi- 
tion. The true wings were apparently gradually drawn up 
under the elytra and folded. This was accomplished by 
expansion and contraction (lengthening and shortening) of 
the abdomen. During this process, which required several 
hours, the true wings remained very flabby, even at the main 
supporting veins. They apparently were kept moistened by 
some substance which did not harden. At 1 p. m. the tips of 
the true wings were still visible, but by 8 a. m. the following 
day they had been entirely retracted to their normal adult 
position. By this time the callow adult was al)le to walk very 
feebly, but did not attain its full strength until a day or two 
later. At the time the young adult arises, the head and pro- 
thorax shows considerable color as does the metasterum and 
the pygidium. The elytra, abdomen and legs were a faint 
yellowish brown. All these parts gradually grew darker, but 
the insect had not yet attained its full color a week later 
(June G). 

Although determined efforts were made to induce the new 
generation of adults to enter new larch, we were unsuccess- 
ful. At flrst young adults were confined in cages with suit- 
able pieces of wood, but they refused to breed in it. As it is 
a well-known fact that other species of Eccoptogaster feed 
for a time upon new growth of their host tree, young adults 
were confined with portion of limbs, including new growth 
and new leaves. However, they resolutely refused either to 
feed upon this material or to breed either in freshly killed 
or less recently killed larch, and we were therefore unable to 
make thorough observations upon their habits and behavior. 
A few broods were, however, started in the old parent host, 
but these were not discovered until jSTovember, 1917, and 
therefore were of no value except as they prove that these 
small scolytids may l)reed for two successive years in the 
same host. 

A careful study of the engravings give the results tabulated 
below : 



hisecfs Bred from American Larch 53 

Number of engravings studied 156 

Number of engravings having one-egg gallery 25 

Ninuber of engravings having two-egg galleries Ill 

Number of engravings having three-egg galleries 20 

Total number of egg galleries 307 

Minimum length of egg galleries 2 mm. 

Maximum length of egg galleries 00 mm. 

Average length of egg galleries 27 . 36 mm. 

Average length of egg gallery in uniramous burrow 34.00 mm. 

Average length of egg gallery in biranious burrow 27.97 mm. 

Average length of egg gallery in triramous burrow 22.35 mm. 

Minimum number of egg niches in one egg gallery 2 

Maximum nvnnber of egg niches in one egg gallery 126 

Average number of egg. niches in one egg gallerjr 30.65 

Average number of egg niches in egg gallery of unira- 
mous burrow 40. 36 

Average number of egg niches in egg gallery of biramous 

burrow 31 . 54 

Average number of egg niches in egg gallery of triramous 

burrow 23 . 46 

Average number of egg niches in entire uniramous engrav- 
ing 40. 36 

Average number of egg niches in entire birasiious engrav- 
ing ." 63 . 08 

Average number of egg niches in entire triramous engrav- 
ing 70.38 

Thus it would appear that just as in P. rufipennis each 
female of E. picece produces a greater uuuiber of eggs when 
she shares her mate with no other female. Here also, how- 
ever, the greatest individual reproductive efficiency is shown 
in burrows occupied by one male and two females and the 
least when more than two females are present. This is 
shown by the following data: 



Number 
of egg niches 


Occupants of burrows Eggs produced 
Male Females per individual 


40.36 
63.08 
70.38 


-4- (1 + 1) = 20.18 
-^ (.1 4- 2) = 21.03 
-^ (1 + 3) = 17.59 



The larval burrows start out at right angles to the egg- 
gallery. At first they are parallel to each other but soon 
])ecome winding in their course, often crossing and recross- 
ing each other. They are rather longer than is usual for the 



54 College of Forestry 

larval burrows of scolytids of their small size. The data 
tabulated below will give the facts obtained by a careful 
measurement of forty larval mines : 

Minimum length of larval burrow 58 mm. 

Maximum length of larval burrow 103 mm. 

Average length of larval burrow 75.8 mm. 

Of the forty burrows measured nineteen were between 60 
and 79 mm. long, ten were less than 70 mm. long, three 
were between 80 and 89 mm. long, five were between 90 and 
99 mm. long, and three were more than 100 mm. long. 

The same beetles are associated with E. picece as with 
P. rufipennis with the exception of those found typically 
only in the lowermost part of the trunk. These include 
Dendroctonus simplex, Monoliammus scutellatus, and 
Asemum rnoeshirn. Of these probably the latter is the only 
one which would not likely to be associated with E. piceoe, 
as it is found only a few feet at most from the ground. 
E. picece is found more often associated with P. rufipennis 
than with any other insect. The latter starts its burrows 
somewhat earlier in the season and naturally when it is 
l^resent in numbers sufficient to occupy all or nearly all of 
the bark of the entire trunk the presence of its brood often 
very much limits the available breeding places of the former. 
Thus, in most of the trees studied E. picece had been thus 
excluded from the trunk even well up in among the branches 
and was not found except in the tops and in the less desirable 
limbs. In other cases where the earlier infestation of the 
P. rufipennis was not so heavy, the two small scolytids were 
found associated in the upper, middle and even to some extent 
in the lower trunk. In such cases it is interesting to observe 
that the brood of E. picece becomes more and more numerous 
in the upper trunk as that of P. rufipennis becomes less so. 

Of the other associated borers the relations with the five 
species of buprestids which are characteristic of the insect 
association in the tops and limbs are perhaps most close. 
These in their relation to E. picece must be classified as 
robbers, it being understood that this relation on the part 



Insects Bred from American Larch 55 

of the larger borers, is a more or less casual or incidental 
one, in that the presence of their burrows in the inner bark 
destroys material which would otherwise serve as food for the 
scolytids. The fact that the most usual direction of these 
larger burrows is longitudinal increases the likelihood of 
disaster to the small larvae. On the other hand, the fact 
that the flatheaded and roundheaded larvae are two-year 
forms, is to the advantage of E. piceoe in that the latter is 
usually associated in the first year of the life of the two-year 
forms, when the larvae of these are small and comparatively 
not so voracious — it being a well-known fact that by far 
the greater per cent of the burrow is made during the latter 
part of a borer's life history. 

Phyllohcenus dislocatus is the only predator found asso- 
cited with E. piceoe. The parasites associated include 
SpatJiius tomici, SpatJnus sp., Spintherus pulchripennis, 
Heterospilus sp., Cheiropachus sp., an undetermined ptero- 
malid, and the fly Medeterus sp. It is impossible to state 
which of these are parasitic upon E. piceoe, but a number of 
cocoons were found in the burrows of this scolytid as well as 
in those of P. ruflpennis in the same material, but we are 
unable to connect these up with the adults arising from 
them. 

Crypturgus pusillus Gyll. (C. atomus LeConte) 

Crypturgus pusillus is cosmopolitan in its distribution. 
Ratzeburg (1839, pp. 196) recorded it from Germany, Bar- 
bey (1913, pp. 143) has taken it in France, and E. P. Steb- 
bing (1904, pp. 498) has written a short account of its habits 
as he observed them in North and West Himalaya. It has also 
been recorded from Japan by Swaine (1909, pp. 44), and in 
North America Packard (1890, pp. 727) reports the distri- 
bution as extending from Canada to Massachusetts and New 
York. Later literature has extended the range over a con- 
siderable portion of northeastern North America, specifically 
given as Canada and Maine south to West Virginia and 
westward to Ohio (Felt, 1906, pp. 360). 



56 College of Forestry 

The European host trees as listed by ISTiisslin (1913, 
pp. 259) are spruce, pine, fir and larch. E. P. Stebbing 
(1914, pp. 498) adds blue pine (Pinus excelsa) and spruce 
(Picea morinda) from India. In America the host trees 
recorded are: white pine, balsam fir, hemlock (Packard, 
1890), pitch pine, scrub pine, yellow pine, table mountain 
pine, black spruce and iSTorway spruce (Hopkins, 1893, 
1899). 

This minute bark beetle, one of the smallest of our sco- 
lytids, has a very characteristic habit. It usually gains 
entrance to the inner bark in which it constructs its breed- 
ing quarters through some previously made opening. This 
is usually either the entrance hole or exit hole of the aban- 
doned burrow of some other scolytid. However, a number 
of cases have been observed in which the burrow utilized in 
this manner was still occupied by its original constructors 
and their brood. In several other eases newly started colo- 
nies of (7. jmsillKs were observed which were constructing 
their breeding quarters in lialsam fir as an oif-shoot from the 
mines of small larvae of Monohamnius scutellaius. In these 
latter cases the so-called " ventilation openings " through 
which the coarse " sawdust " of this sawyer is extruded 
served as the place of entrance. 

However, in most cases access to the inner bark is obtained 
through the burrows of another scolytid. Thus it appears 
always to enter the bark later than other bark borers and 
often does not enter until a season later. In larch it was 
found most frequently making its engravings from the aban- 
doned burrows of P. mjipennis, although it was also asso- 
ciated with those of D. simplex and E. picece in a like 
manner. In several cases it was found associated with the 
living brood of the two former of the species mentioned. 
The brood of this insect have never been taken by us from 
really dry bark, but always from bark containing consider- 
able moisture. For this reason it is to be found associated 
with the burrows of E. picece only in the thicker barked 
regions of the trunk, and as this latter is usually prevented 
from breeding in such places by the earlier preemption of 



Insects Bred from American Larch 57 

these parts by P. rufipennis, the association of C pusillus 
and E. picece is not common. 

The burrows of C. pusillus are in the inner bark but are 
seklom on the surface of the sajiwood. Usually as has been 
pointed out by Stebbing (1914, p. 500) a thin layer of the 
innermost bark remains between the egg-gallery and the sur- 
face of the wood, so that often infested bark may be stripped 
off without discovering the brood. 

In attacking the bark the beetles seem to assemble in the 
burrow of some other insect in groups or colonies comprising 
from five or six to as high as thirty or more individuals. 
Perhaps the smaller numbers are more common, but several 
examples of colonies of twenty or thirty have been observed 
and recorded in our field notes and several engravings made 
by such groups have been obtained. Two of such engravings 
are especially interesting. One, from spruce (Fig. 12), 
shows twenty-two egg-galleries radiating from the nuptial 
chamber of an abandoned Imrrow of P. 7'ufipennis, while 
several more originate from the one egg-gallery made by the 
original inhabitant. In another case taken from larch 
(Fig. 13) twenty-five egg-galleries of C. pusillus originate 
from the nuptial chamber of P. rufipennis. 

The question suggests itself whether these groups of from 
six to thirty or more individuals represent a family or a 
colony made up of a number of families. Stebbing believes 
that the groups rej^resent family groups consisting of one 
male and six or more females, while other writers are non- 
committal on the subject. With no conclusive evidence upon 
the subject, we are inclined to the view that these groups 
represent colonies of numerous individuals of both sexes. 
We are not prepared to state whether or not this species is 
polygamous, but believe that the relations existing in these 
colonies are more or less indiscriminate. 

Various authors seem to agree in describing the egg- 
galleries of this insect as short, sinuous burrows about one- 
half inch long (Packard, 1890, p. 825; Stebbing, 1914, 
p. 499). Our observations do not entirely agree with these, 
however. Where the beetles are relatively few in number 



58 College of Forestry 

and where their egg-galleries arise from an egg-gallery of a 
larger form (Fig. 11), the brood burrows constructed are 
likely to be relatively short. The reason for this is believed 
to be that these small beetles tend to live socially in a com- 
mon " assembly chamber " and where this is of adequate size 
for the members occupying it, the burrowers do not extend 
their mines to any great distance from the general meeting 
place: i. e., each female may construct several short galleries. 
On the other hand, when the numbers are greater and the 
central assembly chamber inadequate to accommodate all 
members of the colony at once, the females are likely to 
construct their egg-galleries longer and to lay all of their eggs 
in one gallery. Indeed, in some cases, the gallery as finally 
made may represent the joint work of several females. This 
very likely is the case in the branched galleries which are 
by no means uncommon in the larger engravings having 
numerous egg-galleries, several of which may be seen in 
Figs. 12 and 13. 

In the material at hand, the length of the egg-galleries 
varies from less than half an inch to two and three-fourths 
inches, i^o satisfactory counts of the number of larvae to 
a gallery could be made because the numerous larvae had 
destroyed most of the egg niches with their winding larval 
mines. These larval burrows are not on the surface of the 
sapwood but in the middle region of the iimer bark. 

Our observation seem to indicate that this insect spends 
the winter usually in the beetle stage, as adults begin to 
appear under the bark during the late summer, and these 
emerge the following spring. In the region of Cranberry 
Lake, the senior author has taken a number of colonies of 
these just after they had invaded the abandoned or still 
occupied burrows of other insects. In one case (June 9, 
1915) a group of about twenty individuals were observed in 
the burrow of a larva of Monoliammus scutellatus. Only a 
few of these had started egg-galleries, the remainder being 
grouped together in a little recess in the side of the burrow 
of the roundheaded borer near the ventilation opening. 



Insects Bred from American Larch 59 

Several bark beetles have already been mentioned as asso- 
ciated with C. pusillus in larch. In addition to these 
Asemum moestiim and Serropalpus barbatus were bred from 
the same material, but these being wood-boring forms, their 
relations to the minute scolytid would not be at all close. 
Phyllobaenus dislocatus is the only predator associated and 
no parasites were bred from the same material. 

Drycoetes americanus Hopkins. 

Dryocoetes americaiius, according to Hopkins (1915, 
p. 51) is the eastern Xorth American species which has 
heretofore been confused with D. septentriones and D. auto- 
graphus. It has been recorded as the latter species, from 
Alaska, Hudson Bay Territory, Lake Superior, x^ew Jersey, 
southwestern Pennsylvania, Virginia and West Virginia 
(Felt, 1906, pp. 672). It is probably found through the 
Rocky Mountain region also, for Fall and Cockerell (1907, 
pp. 217) lists it among the Coleoptera of 'New Mexico, and 
Hopkins (1915, pp. 51) states, " Specimens from the Rocky 
Mountain region show minor differences that are hardly dis- 
tinctive enough to justify the designation of a different 
species." Several species of coniferous woods have served 
as hosts for this scolytid. It was first recorded from red 
spruce {Picea ruhens) in West Virginia in 1890 by Dr. 
Hopkins. In 1891 he reported a parasite — Spathius cana- 
densis Ashm. — from the bark of dead Piceae [Abies] excelsa 
in mines of D. autographus. Later it was taken from partly 
living and dead bark of black and ISTorway spruce and had 
also been found in pitch pine (Hopkins, 1899, pp. 445). 
It has also been taken from white pine and red spruce by 
the senior author at Cicero Swamp, IST. Y., in September of 
1914; at Cranberry Lake, N. Y., in June, 1915 and 1916; 
and in Greene Co., IST. Y., in 1914 and 1915. 

Very little in detail is recorded about the habits of this 
insect. It has generally been considered as preferring 
greatly weakened or dead bark in which to make its burrows. 
Another prominent characteristic is that the beetle almost 



60 College of Forestry 

invariably attacks the lower portion of the tree, even extend- 
ing its galleries several inches below ground in extreme 
cases (Hopkins, 1899, p. 252). In the larch studied the 
insects were found under the thin bark of one of the larger 
roots that was free of the soil for a short distance. No defi- 
nite pattern was noticed in the burrows, however, only a very 
few specimens were taken and the material upon which to 
base any opinion regarding the engravings was quite 
insufficient. 

In the Adirondack and Catskill regions this species is one 
of those most often found breeding in the stumps and trunks 
of felled spruce and white pine. Immense numbers are 
found in spruce, especially where this is of a size having 
thin bark and where it is on or near the ground. Skidway 
timbers and other similar structures near the ground are 
very often infested. Other bark beetles often found asso- 
ciated in spruce and j)ine are P. rufipen7iis, Ips pini, Ips 
ccelatus, Fityogenes pioicfipeunis, Hylurgops pinifex. and 
Dryococtes affaber. Adults have been taken by the senior 
author from their old burrows in the bark at various times 
from September to July. 'New colonies are established dur- 
ing June and early July in the Canadian Zone regions of 
jSTew York. 

Only a few insects were found actually associated with 
D. americanus in larch, doubtless because the only larch 
found infested was an exposed dead root of a living tree 
which on account of its size did not offer breeding facilities 
for many insects. Leptura vittata was bred from the same 
material, some of the adults of this two-year form emerging 
the same year and some the year following the emergence of 
the D. americanus. The larva of an unidentified elaterid, 
possibly predaceous, was taken and a fly Fliorhia fusciceps 
Zett. was bred from this material, while a small portion of 
exposed and decaying wood yielded adults of the weevil 
Dryophthorus americanus. 



Insects Bred from American Larch 61 

Dryophthorus.americanus Bedel. 

The range of this eossoniiiid includes Eastern Canada and 
the Eastern United States as far south as Florida and as far 
west as Wisconsin. It has been reported as occurring specifi- 
cally in Pinus 7'igida (Chittenden, 1890, p. 172) and in 
general as being found under the bark and in decaying wood. 
(Insect Life, Vol. 1, p. 198.) 

Very little specific information can be culled from the 
literature regarding the habits and life history of this insect. 
Further than that the adults may be obtained from beneath 
the bark and in the dead wood (especially of pine) during 
the winter and early spring, no information seems to be at 
hand. Specimens were obtained by us from three separate 
lots of material. In one case under bark killed only the 
previous year and infested with D. simplex and P. I'ufi- 
pennis. The small weevils perhaps fed upon the inner bark 
which as yet had only begun to decay. In both the other 
cases, exposed and decaying wood was the part infested (Figs. 
29, 30). Here the beetles were taken from their burrows, 
which ran in all directions through the punky wood, without 
conforming to any discoverable pattern. 

Adults were taken from breeding cages after emerging 
from their larval hosts July 3 and 7, 1916. Other speci- 
mens were taken from their burrows November 2, 1916. 

Insects obtained from the same material include Dryo- 
coetes americanus, Leptura vittata, Stenocellis hrevis, 
Tenehrio tenehriodes, the elaterid Adelocera hrevicornis, an 
unknown elaterid larva and the fly PJiorbia, fusciceps. Of 
the beetles mentioned all l)ut Dryocetes americanus are wood- 
inhabiting forms and may bear very important relations to 
each other. The association with L. vittata and Dryocoetus 
americanus is perhaps not so common as with the other 
three beetles, though doulitless the larvae of the cerambycid 
prepare the wood for its later occupancy by the cossoninid. 
Its occurrence in the same bark with D. simplex and P. rufi- 
pennis is still less to be expected and perhaps may be 
explained by the individual of Di^yoplithorus americanus 
hibernating in the abandoned portion of the burrows of one 



C2 College of Forestry 

of these scolytids. Perhaps the association with Stenocellis 
brevis is the most common, due to the fact that their habits 
and food are simihir. However, any actual rehitions which 
the two forms may have are doubtless accidental or casual. 

Stenocellis brevis Boh. 

Stenocellis brevis ranges from ISTew England and Canada 
to Michigan and Kansas and south as far as Florida (Blatch- 
ley and Leng, 19 10, pp. 545). This cossoninid has been 
taken from a great variety of host trees. Packard (1890) 
lists it from dead wood of elm (pp. 28-4), wood of butternut 
(pp. 342), partly rotten stumjj of red maple (pp. 391), 
and from' linden (pp. 381). Chittenden (1890, pp. 99) in 
addition to these records it from basswood, beech, birch, syca- 
more and willow. Hickory and poplar were added to the 
list by Harrington (1896, p. 75). Felt (1906, pp. 494) 
adds ash, and Platchley states that Zabriskie has found it in 
apple wood (1916, pp. 545). H has been taken by the 
authors from larch, hickory, apple and horsechestnut. No 
specific record has heretofore reported it from coniferous 
woods so far as can be learned from the literature. 

From observations in the field as well as from literature 
on the subject it ajapears that decaying wood or at least 
exposed dead wood is necessary for the insect's welfare. The 
burrows have been seen in apple and horsechestnut where 
the outer wood was still very hard and contained no evidence 
of fungi. In larch, however, it was found in one instance in 
the decayed wood of a small tree, about three inches in diam- 
eter, where the wood was soft and in such condition that the 
fibres could be readily pulverized l)etween the fingers. In a 
second case they were taken from dead sapwood caused by 
the peeling of a strip of the bark down the trunk of a larch 
about fourteen inches in diameter. At this time both adults 
and larvae were found scattered through the galleries, the 
adults occasionally found in groups of three or four in 
enlarged chambers in the wood. The sapwood had begun to 
decay and the live bark had started to close over the wound, 
which had apparently been made about six years previously. 



Insects Bred from American Larch 63 

The beetles were taken from one to five feet above the 
ground. This was as far up as the tree had been peeled. 
They were found under much the same conditions in apple 
and horsechestnut wood. 

It is believed that the beetles may possibly remain in the 
wood for a period of two or more years. At least they have 
been observed in a horsechestnut tree for two consecutive 
years. Evidently the insect lives in a somewhat social or 
colonial manner, as several groups of three or four were 
found in the enlarged burrows. The galleries are about 1.5 
mm. to 2 mm. in diameter and extend irregularly up and 
down the tree with many transverse galleries connecting the 
longitudinal ones. Occasionally wider galleries occur. In 
the instances observed the wood was more or less riddled by 
the galleries. The eggs are probably laid in the primary 
gallery and the larvae bore out into the wood in all directions. 
Adults have been taken from larch February 26, April 28 ; 
larvffi on April 28. Blatchley (1916, pp. 51:5) has taken 
the adults June 15 to July 30, beneath bark and by sifting 
rotten wood. 

It is quite probable that Serropalus harhatus^ often pre- 
cedes S. hrevis, especially in weakened trees, and its galleries 
make the wood a more suitable breeding place not only for 
this cossoninid but for other forms living in decaying wood. 
It is also possible that Asemum moestuin may precede S. 
hrevis in a like manner. Both of these forms would bear a 
very important relation to the curculionid by preparing the 
wood for its purposes. 

Insects actually associated with S. hrevis were Dryoph- 
tJiorus americanus, Tenehrio tenehriodes, and Adelocera 
hrevicornis. These all from dead wood which had begun to 
decay and which was more or less riddled with insect bur- 
rows. S. hrevis may be preceded by any one of a great 
variety of fonns atacking the dying or newly killed tree. 
It seems to prefer rather dry, punky wood, and perhaps for 
this reason seldom or ever enters the wood still covered by 
the bark. When it is preceded in the wood by the larvse of 
such forms as Leptura vittata, Asemum moestum, or 8erro- 



04 College of Forestry 

palpus harhatus, the wood is in a condition more tlian usually 
favorable for its uses due to the burrows already present 
and to the introduction of decay by their i^resence. 

Phymatodes dimidiatus Kirbv. 

Hamilton (1894, p. 31) records the distribution of 
Phymatodes dimidiatus as IJnalaska, Vancouver, Washing- 
ton, Idaho, through the Rocky Mountains to Mexico, thence 
across the northern part of the continent to Maine and Mas- 
sachusetts. Hopkins (1893a, p. 192) reports it from Wash- 
ington and Felt (1906, p. 609) from various points in Wew 
York and New Jersey. Evidently spruce has been practi- 
cally the only host recorded for this cerambycid (Hopkins, 
1899, p. 438), although it undoubtedly breeds in other 
species, especially in the Kocky Mountains. Davis (1891, 
pp. 81) states that he has taken it '^ from oak posts of a 
summer house." The senior author has taken the adults 
from beneath the bark of spruce in the Adirondacks. 

P. dimidiatus lives during the greater part of its larval 
existence directly under the bark, excavating its winding 
galleries for the most part in the same direction as the grain 
of the wood. The eggs are laid during June under the small 
flakes of bark or injured places and even occasionally in the 
deserted or still occupied burrows of P. rufipennis in trees 
that have been killed the previous year. The larva, from 
the first grooves the sapwood, the burrow becoming deeper 
and wider as the larva becomes larger (Figs. 14, 15). How- 
ever, during its larval existence the burrow is always directly 
under the bark, and it is not until the insect is ready for 
pupation that it extends its burrows into the sapwood. Just 
before it transforms into the pupal stage, which may occur 
either before or after hibernation, the larva burrows for about 
a quarter of an inch below the surface of the sapwood and 
here enlarges its mine to form a pupation chamber. Before 
pupation, however, the larva burrows up to the bark and 
packs the end of the gallery with coarse frass so that the 
adult when it is ready to emerge may work its way out with 
a minimum amount of labor. The rest of the larval mine is 



Insects Bred from American Larch 65 

packed with fine, dust-like frass. Winter is most usually 
passed either in the larval or adult stage. 

One year is usually required in this locality for the com- 
pletion of its life history. However, it should be realized 
that this represents only the normal condition m the locality 
in which this form was studied (Crittenden and Syracuse). 
It is quite likely that it may occasionally, or even may 
usually, require two years for its development m the colder 
reo-ions of the State. Dogmatic statements regarding the 
length of larval life are dangerous. Adults emerged May 26, 
31 and June 8 and 15, 1916, from larch killed during 1914. 
The eggs of P. dimidiatus had doubtless been laid m 1915, 
as was" shown in one case by the relation of the larval 
burrows of this species to the engravings of P. rufipennis 
occurring in the same material. . , ^ ^ -l 

P dimidiatus may be preceded in the bark oi larch by 
several insects, notably by P. rufipennis mentioned above, 
by Dendroctorous simplex, Eccoptogaster picew and by Ase- 
mum moestum. On the other hand, it may in other cases enter 
the tree during the same season as any or all of these. It 
seems rather to prefer trees (whether spruce or larch) which 
are thoroughly dead, and, therefore, when any of the above 
species precede it in the bark they by so doing benefit rather 
than injure it as a place of breeding for P. dimidiatus. Un 
the other hand, where the larvae of this cerambycid occur m 
the same material as the brood of the various scolytids men- 
tioned, it may be injurious to the latter by robbing them ol 
their food. Other borers which have been bred from the 
same material include the cerambycid Leptostylus sex- 
guttatus, the melandryid Serropalpus harhatus, and the two 
siricids Urocerus alhicornis and Sirex ahhotit. 

Two predators, Phyllohaenus dislocatus and Cymatodera 
Ucolor, were associated with P. dimidiatus. The parasites 
derived from the same material include Bhyssa Imeolata, 
Pseudorhyssa sp., Odontaumerus canadensis, Eurytoma sp. 
and three apparently new species of Doryctes. The rela- 
tions of these parasites have previously been discussed 

3 



66 College of Forestry 

(p. 32) and it has been pointed out that of these all but 
Eurytoma sp. are probably parasitic upon P. dimidiatus. 

Asemum moestum Hald. 

Asemum moestum has been recorded from Canada south- 
ward to Florida. It is known from Lake Superior and 
Packard (1890, pp. 697) has taken it from Colorado and 
states that it undoubtedly breeds in coniferous trees in the 
Kocky Mountain region. LeConte believes that it occurs in 
Alaska (Packard, 1890, pp. 697). The host trees include 
white pine (Packard, 1890, pp. 697), yellow pine and spruce 
(Hopkins, 1899, pp. 438). Apparently larch has never 
been recorded as a host, but it is likely that this borer will 
be found in a large number of coniferous trees throughout 
its range. 

This beetle lives in the larval stage in the base of the 
trunk. We have never bred it from wood more than a few 
feet from the ground. It is then, as will be readily seen, 
most often found in the stumps of its host trees in regions 
which are being lumbered. The adults will apparently 
deposit their eggs only in green, sappy material, and our 
observations show that it very often enters the larch even 
before this shows any visible signs of weakness — sometimes 
a full year before the entrance of Dentroctonus. 

The young larvse on hatching burrow into the sapwood 
and often extend their mines deep into the heartwood. These 
mines, which are somewhat flattened in cross section, are 
more or less winding in their course, but with the general 
direction more usually longitudinal. The larvae are often 
very numerous, in one case six larvse of various sizes being 
taken from a space about six inches square. This beetle 
ordinarily requires two years to complete its larval growth 
and the probabilities are that occasionally a longer time is 
necessary. The pupal stage is passed in an enlarged cham- 
ber at the end of the larval burrows. This is constructed 
in the sapwood quite close to the bark. The adult emerges 
through an- oval hole in the bark. Beetles emerged from 
larch May 29 and June 15, 1916. Numerous other adults 



I meets Bred from American Larch 67 

have been taken by the senior author at Cranberry Lake, 
N. Y., during June and early July, both on the wing and 
from the wood of both pine and hemlock. 

A. moestum is one of the primary insect enemies attack- 
ing the weakened tree. It is often associated in either its 
first year or second year with Serropalpus harhatus, which 
is also a wood inhabiting form. Quite often the burrows of 
these two forms occur in the same section of wood, although 
the melandiyid, of course, bores the wood of a greater region 
of the trunk. Other beetles found to occur in the same 
samples of the trunk are Dendroctonus simplex, Polygraphus 
rufipennis, E ceo ptog aster piceae (occasionally), Phymatodes 
dimidiatus and MelanopJiila fulvoguttata. These may be 
associated with A. moestum during either the first or second 
year of the latter's life; or in the case of M. fulvoguttata, 
the two forms may occur in the same trunk throughout two 
years. It should be borne in mind, however, that A. moestum 
seldom or never spends any considerable time between the 
bark and the sapwood, and therefore its relations with these 
forms (other than S. harhatus) are usually more apparent 
than real. However, where it enters the tree a full season 
ahead of its associates, as often occurs, there can be no 
doubt that its presence in any considerable numl^ers greatly 
weakens the tree and makes this a more attractive host for 
those forms entering later. This is especially true in the 
case of the bark beetles because the larvae of Asemum, work- 
ing in the wood, while they weaken the tree's resistance, do 
not destroy the inner bark. 

Monohammus scutellatus Say. 

Monohammus scutellatus is distributed throughout Canada 
and the Northern part of the United States from coast to 
coast, as far north as the Hudson Bay and Yukon regions 
(Hamilton, 1894, p. 31) and as far south as New Mexico 
and West Virginia (Hopkins, 1893, p. 195). 

The hosts most usually recorded for this cerambycid are 
white pine and spruce. In the Cranberry Lake region and 



68 College of Forestry 

also in the Catskills the senior author has most often taken 
it from balsam fir. There can be no doubt, as is indicated 
by its distribution, that a large numl)er of conifers may serve 
as host. In larch this beetle was bred only from the trunk 
region, but doubtless also occurs in the tops and larger limbs. 
In other hosts it occurs most often in regions having com- 
paratively thin bark. Thus in white pine it is most usually 
found in the tops and limbs, while the two sister species 
M. confusor and M, titillator are more common in the trunk. 
In spruce this is true to a lesser extent, due to the thinner 
bark, and in balsam any part of the trunk and the limbs 
down to a diameter of less than an inch are likely to contain 
larvae, although they are here perhaps more common in the 
trunk. 

The eggs are laid in material in a variety of different 
conditions. Eggs still unhatched and newly hatched larvae 
have been taken from a balsam tree which was still entirely 
alive and green but slightly injured by lumbering operations. 
On the other hand, living, callow adults have been taken 
from their transformation chambers in bnlsam which had 
been down and dead at least four years. The larch from 
which specimens were bred was in similar condition when 
brought to the laboratory, the bark being loose and the tree 
having been dead three or four years. However, in other 
recently killed larches the larvas have been found and liurrows 
in such material from which the larvae have been removed by 
woodpeckers are numerous. 

The adults of this beetle are abroad throughout most of 
the summer and may oviposit at any time between the first 
of June and the first of September. However, the height of 
the breeding season is during July and August. On July 8, 
1914, the senior author took twenty-one specimens of this 
insect in a few minutes while eating his lunch in a small, 
recently-made clearing near the summit of Twin Mountain, 
Greene Co., IST. Y. These beetles were at the time creeping 
over the bark of recently felled balsam and spruce. Several 
Dairs were taken in copulation, and in one case the female 
was ovipositing although still attended by a male. 



Insects Bred from American Larch 69 

Some interesting observations upon the breeding habits 
were made by Mr. A. J. Macl^ab, a graduate student inthe 
Laboratory, and these are supplemented by other observations 
made by the senior author at various times. On February 1 
some branches from a tree which had been cut the preceding 
winter were brought into the Laboratory and placed in a 
breeding cage. On March 7 adults of M. scutellatus began 
to emerge. Some fresh pine from one to two inches in diam- 
eter, was placed in a breeding jar and the beetles were 
introduced, the bottom of the jar being covered with a layer 
of moist earth for the purpose of keeping the humidity more 
constant and to furnish a suitable footing for the beetles. 

When this jar was placed in the sunlight, or when the 
bright light from a tungsten bulb was directed upon the jar, 
the females climbed to the top of the pine sticks and made 
attempts to fly. They were followed by the males, all of the 
beetles showing apparent excitement. After being exposed 
to the heat and light of the tungsten bulb for about an hour, 
copulation began. In this process the male mounts the 
female, grasping her around the prothorax with his fore- 
legs, which are especially modified for this purpose, at the 
same time bending his abdomen downward and forward so 
as to bring the genital openings together. The penis is then 
extruded and sexual connection is established if the female 
denotes her willingness by opening the space between the 
last dorsal and ventral plates of the abdomen. _ When she is 
not ready for sexual intercourse, she often tries to escape, 
and sometimes an especially ardent male may be carried all 
over the limb for ten or fifteen minutes before the female 
becomes complaisant or until he is dislodged. 

Copulation lasts a variable length of time. In several cases 
where the time was noted, it lasted from half a minute^ to 
considerably more than three minutes and was accompanied 
by a pumping movement of the abdomen of the male. The 
same male often copulates with the same female or with other 
females repeatedly. In one case, after a union lasting over 
three minutes, the connection was broken, but the male still 
clung to his mate and was dragged or carried all over the 



70 College of Forestry 

limb for five minutes before he was finally dislodged. Per- 
haps the most peculiar case illustrating the ardency of the 
male was the following: It being desired to examine the 
anatomy of the })enis, a pair of beetles in copulation was 
chosen and the j^enis of the male was grasped with a pair of 
forceps and removed from the body. The male was then 
replaced in the jar with his mate. For a few minutes he 
rushed about in an excited manner acting as if in consider- 
able pain. In a short time, however, he quieted down and 
his behavior became more normal. Just eighteen minutes 
after the amputation of his penis he again mounted the 
feuuile and attempted copulation. 

During actual co})idation the female, however anxious she 
may apparently have been to escape, remains stationary or 
nearly so. She usually liehaves with the greatest apparent 
inditl'erence, very often continuing to feed by biting off bits 
of ])ine bark. Both males and females feed readily in 
captivity on the bark of fi'esh pine limbs, although perhaps 
the female is more voracious. 

In de])ositing her eggs the female usually chooses a point 
near the juncture of twig with the limb or some location 
which has been roughened by having the bark chewed off in 
feeding (Fig. 17). In either case she bites away the outer 
bark constructing what might be spoken of as a shallow pit 
which extends into the inner green bark. She then turns 
around, i)laces the end of her ovipositor in this shallow cavity 
and pushes it dee])er and deeper into the inner bark in a 
direction parallel to the bark fibres. In four cases the depth 
of this egg puncture was measured and was found to vary 
from five and a half to seven and a half millimeters. Some- 
times several eggs are de})osited in punctures arising from 
one pit. In such cases they are arranged radially around 
the common point of entrance. In some cases no pit is con- 
structed, but the ovipositor is thrust through the thin, outer 
bark as far as possible into the inner, green bark. The pro- 
cess of oviposition was timed in several cases and requires 
on an average about two minutes. 



Insects Brxd from Americari Larch 71 

Small sections of the bark containing eggs, the time of 
depositing of which was known, were placed in a moist 
chamber for incubation. The incubation period in the 
laboratories was about twelve days. An Qg^ laid at 4 p. m. 
March 8 hatched March 20 and others required a similar 
length of time. 

Adults bred in the laboratory and confined in captivity 
with abundance of proper food lived from fourteen to thirty- 
one days, the average being between fourteen and twenty 
days. The male from which the penis had been removed 
lived the longest period of any — thirty-one days. 

The larvae burrow between the bark and the sapwood, 
grooving each about equally. The galleries are irregular, 
sometimes becoming rather long and winding, w^hile in other 
cases they are confined to a small area. Very soon after 
hatching the larva makes an opening to the outside through 
the bark. This is always small, never being large enough 
for the passage of the larva's body, and is used in thrusting 
out the chips or " sawdust " of the sawyer, the larval mine 
near this opening being kept clear of this material (Fig. 16). 
Often this frass will collect to form piles of considerable size 
under the infested logs, resembling piles of sawdust. Some 
time during the summer the larva carries its mine into the 
sapwood, often for a depth of several inches when the burrow 
is in the trunk. This mine is used as a retiring chamber 
and, on occasion later, as a hibernating chamber and eventu- 
ally as a pu])ation chamber. The winter may be passed as a 
full-grown larva or as a larva in any stage of its growth. 

The length of the larval life varies quite remarkably from 
one to three years. ]^rormally the larvaj complete their 
growth and transform to the adult in a single year, but in 
some cases this may be unduly lengthened by several causes. 
Numerous cases have been noted where blown-over balsam 
trees which happened to lie in locations to which the sun 
never has access have contained the same generation of larvse 
for two and even three years. The larval period may also 
be unduly lengthened by other unusual conditions. On two 
separate occasions, once in the Adirondacks (balsam) and 



Y2 College of Forestry 

once at Syracuse (pine), infested wood knoA^na to contain 
full-grown grubs was barked and one year later still con- 
tained living larvae or young adults. The barking of the 
wood created an unusual condition in several respects, but 
especially it rendered the wood more subject to dessication, 
and this abnormal dryness was doubtless the factor which 
retarded the development of the larvse. It is interesting that 
the larvse and young adults under these conditions were 
apparently normal in all respects except as regards time of 
emergence. 

As the larva continues to grow the " retiring burrow " in 
the sapwood is enlarged from time to time to accommodate 
its larger bulk, and when the larva reaches full growth this 
is carried deeper into the limb or trunk to form the pupation 
chamber. This, in burrows in the trunk, may lie in the 
heart wood several inches from the bark. Always before 
pupation a passageway, circular in section, is extended out- 
ward toward the bark, usually ending a fraction of an inch 
from the inner bark. This is to act as an exit for the adult 
when it emerges. The larval entrance to the pupal chamber 
is then plugged with excelsior like frass and the larva pupates 
in the deeper part of the burrow. The emergence hole 
through the bark is nearly exactly circular in outline and 
from 4.6 to 6.5 mm. in diameter (Fig. 16). 

Eccoptogaster picece and Polygraphus rufipennis precede 
M. saitcllatiis in larch and Serropalpus barbatus was bred 
from it the same season.* In balsam it is most often asso- 
ciated with Pitogenes punctipeiniis Lee. and with Urocerus 
albicornis. In pine M. scutellatus is often associated in the 
limbs with the sister species M. titillator, Ips pini Say, Pito- 
genes hopkinsi Swaine, and others, and in the trunks with 
M. titillator, M. confusor, Ips longidens Swaine, Graphi- 
surus faciatus De G., Ehagium lineatum Oliv., Pytlio ameri- 
canus Kirby, etc. 

* In Tree IX it was associated with Polygraphus rufipennis , Neoclytus 
longipes and Xylotrchus undulaUis. 



Insects Bred from American Larch 73 

Leptura vittata Oliv. 

Leng (1890, pp. 199) has recorded the habitat of this 
cerambycid as Canada, New York, New Hampshire, Maine, 
Massachusetts, Pennsylvania, Virginia, Georgia, Alabama, 
Louisiana, Illinois and Wisconsin. Very little is known 
regarding its host trees, and evidently larch is the first wood 
from which this insect has been bred. Blatchley (1916, 
pp. 1059) has taken the adult from the foliage of Virginia 
creeper and other shrubs. The senior author has taken it in 
large numbers from the blossoms of wild spirsea in the Cats- 
kill mountains during July and August. 

Specimens of this insect were bred from a partly decayed 
piece of root that had been free of the ground for some 
time. The tree from which it came was still alive. The 
root was covered with thin bark and is about four inches in 
diameter. Adult specimens of Dryocetes americanus were 
taken from beneath the bark in the spring before L. vittata 
emerged. Only a small piece of root was studied, but some 
half dozen larvae and adults were derived from it. Apparently 
the life history is not completed in one year, for wood con- 
fined in the breeding cage produced adults both in the early 
summer and in the following winter in the laboratory. It 
is very likely, however, that two years are sufficient for the 
completion of the various stages of its development. The 
larvae burrow through the sapwood and frequently they are 
found deep in the heartwood. The pupal chambers, how- 
ever, are found directly under the bark. The larval burrows 
are very similar to those of other cerambycids burrowing in 
the sapwood of trees. Fine dust-like frass is tightly packed 
in the larval burrows, while in the pupal chambers we find 
each end packed with the characteristic excelsior frass. 
Adults emerged June 15 and 28 in the outdoor breeding 
cages and January 10 in the laboratory the following winter. 

Dryocetes americanus and Dryophthorus americanus and 
an unknown elaterid larvae were found associated. Phorhia 
fusciceps, a fly, was also taken from the wood, but had 
probably emerged from decaying fungi. No associated 
parasites were obtained. 



74 College of Forestry 

Leptostylus sex-guttatus Say. 

Leptostylus sex-guttatus has been recorded from Canada, 
Massachusetts, New York, New Jersey, Pennsylvania, Dis- 
trict of Cohimbia, Ohio, Michigan, Wisconsin and New 
Mexico (Leng and Hamilton, 1896, p. 119). Blatchley 
(1910, p. 1072) reports it also from Indiana. Apparently 
little is definitely known regarding the larval host of this 
cerambycid. Eeiitenmliller (1890, p. 79) states that it 
"breeds in 'the wood of locust." Wickham (1897, p. 152) 
says that it " may be taken on freshly cut pine," and ]\Iorris 
(1916, p. 197) records having taken a number of specimens 
from a fallen ])hie. Our record from larch is apparently 
the first time it has been recorded as having actually been 
bred from a conifer. It has also been bred from the limbs 
and trunk of white pine by Mr. A. J. MacNab, a former 
student working in our laboratory. This beetle has been 
found to breed only in the thin-barked parts of the larch and 
the female seems to show a preference for the freshly killed 
or weakened tops or limbs in which to deposit her eggs. 
However, three specimens were also obtained from the trunk 
of a small tree about two inches in diameter which had l)Oon 
killed by shading. 

Upon hatching the larva begins to construct its larval 
gallery between the inner bark and sapwood. At first this 
grooves both bark and sapwood to an equal extent, but as the 
larva increases in size a greater per cent of the depth of the 
burrow is excavated from the wood and a less per cent from 
the thin bark, so that when the larva reaches full size about 
nine-tenths of the thickness of the larval mine is in the sap- 
wood. The course of the larva is very tortuous (Fig. 18) 
and is sometimes unusually long for a borer of its size, 
even though it be a two-year form as in the present case. 
In one case where all parts of the larval mine could be readily 
traced it measured 290 mm. to the entrance of the pu[)al 
chamber. 

At the end of the second season the larva reaches full 
growth, but before pupating it bores into the sapwood, usu- 
ally not more than a half inch from the surface to construct 



Insects Bred from American Larch 75 

a pupation chamber. It usually continues this burrow paral- 
lel to the surface for about 40 to 50 mm., then extends it 
upward to a point just beneath the ])ark. The pupal cham- 
ber for about half its lenfijth is solidly packed with fine frass, 
as was the entire larval burrow. However, the " sawdust " 
in the entrance to the pu|)al burrow is of a lighter color 
than that in the larval mine, because it is derived entirely 
from the sapwood, whereas the latter comes partly from the 
bark. The adult on arising gnaws through the thin layer 
of sapwood left by the larva, perforates the bark and emerges 
through an oval exit hole about 21/^ by 3 mm. in diameter. 

The following borers were associated with L. sex-guttatus: 
Polygraphus rufipennis, Eccoptogaster picecc, Pogonocherus 
■mixtus, Neoclytus longipes, Phymatodes dimidiatus, Mela- 
nopliila fulvoguttata, Chrysobothris hlanchardi, C. sex- 
signata, C. dentipes, and Antliaxia quercata. All of these 
except the two scolytids and P. dimidiatus are two-year forms 
and live in the limbs and tops during the same two seasons. 
P. rufipennis and E. piceoe are associated with these larger 
borers usually only during the first year. Occasionally, 
however, second broods of each of these are reared in the 
old host. Although this may perhaps occur more commonly 
in the breeding cages than in nature, examples under both 
conditions were found. The brood of either of these scolytids 
is likely to be robbed of their food or actually killed outright 
by the larvse of Leptostylus sex-guttatus or any of the other 
round-headed or flat-headed borers mentioned above. This 
is especially true during the second year of the larval life 
of the large forms. In this connection it is interesting to 
note that two sister species of L. sex-guttatus, L. aculipes 
and L. macula^ have been reported in similar roles in con- 
nection with two other scolytids (Schwarz, 1890, p. 165). 

The inter-relations of the larger borers are variable and 
more or less accidental. The simultaneous presence of sev- 
eral specimens either of the same species or of difi^erent 
species in the same region may be of advantage in over- 
coming the resistance of the dying or weakened tree. If the 
tree is already so weakened as to offer no considerable danger 



76 College of Forestry 

to the developing larvae, the presence of several is of no 
importance. On the other hand, so many larvse, either of 
the same (Fig. 27) or different species, are sometimes pres- 
ent as to reduce the amount of available food to such an 
extent that the resulting insects are underfed and therefore 
undersized. It is likely that occasionally this condition 
becomes so acute as to result in the actual starvation of some 
of the larvse. 

Predators associated are Phyllohaenus dislocatus and 
Cymatodera hicolor. These are doubtless more dependent 
for food upon the associated scolytids, but it is believed that 
they may also feed upon the smaller flat-headed and round- 
headed borers, especially when these are young. The adults 
would experience difficulty in gaining access to the larvse on 
account of the closed burrows packed with frass, so they 
would probably only occasionally be able to attack them. 
However, the larva3 of clerids are well-lvnown inhabitants of 
the burrows made by other insects, and without doubt they 
occasionally prey upon both cerambycid and buprestid larvse. 

Three parasites were associated with L. sex-guttatus and 
the other round-headed and flat-headed borers occurring in 
limbs and tops. These include Pliasgonopliora sp., Atoreutus 
astigmus and Odontaulacus hilohatus, specimens of each of 
which emerged at about the same time as the two-year borers. 
No conclusive evidence definitely associating any of these 
with their host is at hand. 

Neoclytus longipes Kirby. 

Neoclytus longipes has been recorded from Canada, Vir- 
ginia and Texas by Leng (1887, p. 8). ISTo definite state- 
ment regarding its host w\as found, but Wickham (1897, 
p. 152) and Morris (1916, p. 198) have taken the adult 
from freshly cut pine.* This borer was obtained by us from 
larch brought both from Crittenden and from near Wana- 
kena, showing a wide distribution in the State. 

* The senior aiitlior has taken numerous specimens from the surface 
of the bark of freshly cut balsam and spruce. 



Insects Bred from American Larch 77 

This cerambycid requires two years for the completion of 
its life history. As noted above, it was bred from material 
from two different sources. That derived from Crittenden 
consisted of the limbs of Tree I. This was confined during 
the entire summer of 1916 and during this time gave rise 
to only two borers, Polygraphus rufipennis and Eccopto- 
gaster picece. It was then removed to the laboratory jSTovem- 
ber 2, where the temperature conditions were such as to 
induce the larvae to resume work. Adults of N. longipes 
emerged January 30 and March 16. 

The second lot of material derived from Wanakena con- 
sisted of tops 2-4 inches in diameter of Tree IX, which 
had been blo^vn down during May, 1916, and had become 
infested between that date and the middle of August. This 
material was confined in breeding cages outdoors till early 
in Januaiy, 1917, when it was brought into the laboratory, 
but was again removed to a cold room in the latter part of 
February, where it remained till June. It was then placed 
in an outdoor breeding cage, and on July 3, 11 and 18 
specimens of N. longipes emerged. Thus this form, which 
normally requires two years for the completion of its life 
history, was induced to emerge a season earlier by the treat- 
ment the material received. It should be noted in this con- 
nection that the specimens thus treated are slightly under- 
sized, measuring respectively 7, 8 and 8 mm., while those 
from the other lots of larch were from 9 to 9.5 mm., being 
entirely normal in size. 

N. lo7igipes deposits its eggs in larch which is either dying 
or recently dead. The larvse excavate deep, rather narrow 
burrows in the sapwood just under the bark. The larval 
mines are very long (Figs. 19, 20), in three cases where they 
could be accurately measured being 445 mm., 485 mm. 
and 568 mm. These measurements are rather too small than 
too large, as no attempt was made to measure the smaller 
curves in the course of the grooves. The entire burrow is 
packed full of rather fine frass by the larva, which, on becom- 
ing full grown, burrows into the wood to construct a pupation 
cavity (Figs. 19, 20). This chamber in the wood is also 



T8 College of Forestry 

much longer than usual, varying in cases observed from 45 
mm. to 120 mm. This pupation chamber is solidly packed 
with fine frass for the greater part of its length — only from 
20-30 mm. being free of this material — and in spite of its 
excessive length it usually does not lie more than half an 
inch from the surface of the bark, although it may lie deeper. 
On emerging the adult gnaws through the surface and leaves 
the wood through a nearly circular hole slightly more than 
2 mm. in diameter. 

Larch is attact by N. longipes the same season that it is 
attact by P. rufipennis and E. picece, and thus the larvae are 
often associated with the brood of these scolytids through- 
out their first year of life. It was also associated with the 
following insects emerging at about the same time: Lep- 
tostijlus sex-guttatiis, Pogonoclierus mixtus, CJirysohothris 
dentipes, C. sex-signata, C. hlonchardi, Melanopliila fulvo- 
guttatco and Anthaxia quercata. In the material studied 
these forms were never so numerous that the burrows inter- 
fered with each other seriously, and therefore the inter- 
relations were probably not at all important in an adverse 
way. However, in dying or sappy bark presence of a greater 
number of specimens, up to a number where additional ones 
would interfere with the available supply of food, is of a 
distinct advantage in overcoming the resistance of the tree. 
So long as these all worked in a similar region it would 
make no difference whether the larvae represented a number 
of species or were all of one species. 

Phylloboenus dislocatus was the only predator derived 
from material containing N. longipes. It is probable that 
this is more usually dependent upon the associated scolytids 
for its food, but it is by no means iraprol)a1)le that it will 
attack the larvse of any of these smaller round-headed and 
flat-headed borers whenever it can gain access to their bur- 
rows. The same three parasites were associated with 
A", longipes as with L. sex-guttatus. 



Insects Bred from American Larch 79 

Pogonocherus mixtus Hold. 

Pogonoclierns mixtus has been reported from Canada and 
from nearly every region of the United States except the 
Southeastern States. Leng and Hamilton (1896, p. 135) 
give the distribution as " Canada, Maine, New Hampshire, 
Massachusetts, i^ew York, i^ew Jersey, Pennsylvania, Mich- 
igan, Wisconsin, Missouri, Kansas, Colorado, Montana, 
Idaho, California, Arizona." This species has been taken 
from beneath the bark of vi^illow (Caulfield, 1881, p. 60) 
and " beneath the bark and on the dead limbs of pine 
(Blatchley, 1910, p. 1081). We have bred it both from the 
" shaded out " limbs of white pine and from the limbs of 
larch. 

The eggs are deposited in recently dead thin-barked larch 
or pine. Cracks or other injuries in the bark were utilized 
by the female in ovipositing. In one case in pine the ovi- 
positor had appearently been thrust into the entrance to the 
burrow of Pityophthorus sp. in gaining access to the inner 
bark. The larva on hatching works directly beneath the 
bark, grooving the sapwood deeply. The burrows at first 
are both narrow and shallow, but those made by the full- 
grown larva are from 4 to 7 mm. wide and slightly more 
than 2 mm. deep. The course of the larval gallery is only 
slightly winding, as shown in Fig. 21, and usually the bur- 
row loops back upon its course so that the entrance to the 
pupal chamber often lies not far from the origin of the 
burrow. The burrow is rather short, usually from 110 to 
125 mm. long. The pupal chamber is carried diagonally 
into the wood for a depth of 12 to 15 mm. The larva then 
plugs the opening loosely with medium-fine shreds of wood 
and jjupates. Apparently before pupating the larva has 
arranged itself with its head directed back toward its larval 
burrow for the adult on emerging invariably (so far as our 
observations on fifteen cases go) removes the obstructing 
frass and emerges through a nearly circular opening in the 
bark covering the larval mine. The insect requires two years 
for the completion of their growth and the adults begin to 
emerge about the middle of June. 



80 College of Forestry 

Associated borers, predators and parasites are the same as 
for Leptodylu.s sex-guttatus (see page 75). with the excep- 
tion of Phymatodes dimidiatus. 

Melanophila fulvoguttata Hare. 

Melanophila fulvoguttata is distributed tkroughout eastern 
Canada and United States from Labrador (Sherman, 1910, 
PI). 193) to :N'orth Carolina (BL^nchard, 1889, pp. 193) 
and is common as far west as the Lake Superior region 
(LeConte, 1859). The host trees most commonly attact are 
the hemlock and spruce, of both of which this species is a 
serious enemv. In addition Harris (1862, p. 50) records 
having taken the adults from the trunks of white pine during 
June. It was bred by us, both from the branches and the 
trunk of larch and has been taken by the senior author from 
both hemlock and red spruce in the Cranberry Lake region 
of N^ew York. 

3/. fulvoguttata deposits its eggs in the bark of the trunk 
and limbs of weakened, dying or dead hemlock, spruce or 
larch. It may also breed in balsam fir and white pine, but 
no definite data is at hand to prove this. The larval mines 
of this flat-headed borer are rather wide, shallow and wind- 
ing in their course, and where the larvae are numerous, as is 
very often the case in dying hemlock or spruce, these larval 
burrows cross and recross each other, making it difiicult or 
impossible to follow the course of any particular one. Two 
years are required for the completion of the life histoiy. 
The adults emerge at any time during the summer, having 
been taken by the senior author in the Adirondacks at various 
times between June 15 and September 1. 

M. fulvoguttata may occur under the bark of any part of 
the tree from the base of the trunk to limbs an inch in diam- 
eter. It may therefore be associated with any of the boring 
insects attacking the same tree. In our work it was found 
actually associated in the trunk region with Dendroctonus 
simplex, Polygraphus rufjpennis and Asemum moestum; and 
in the limbs and tops was bred from the same material as 
P. rufipennis, Eccoptogaster picece, Leptostylus sex-guttatus, 



Insects Bred from American Larch 81 

Pogonocherus mixtus, Neoclytus longipes, Chrysobothris 
hlanchardi, C. sex-signata, C. dentipes and Anthaxia quer- 
cata. The associated predators and parasites were the same 
as for N. longipes. 

Chrysobothris blanchardi Horn. 

The distribution of Chrysohotliris hlanchardi was reported 
by Horn (1886, p. 9-1) as Massachusetts, District of Cohim- 
bia and Lake Superior region. Blatchley (1910, p. ^91) 
records specimens from two counties in Indiana. This 
species has been recorded as a borer in white pine in Massa- 
chusetts by Blanchard (1889, p. 31) and as occurring "on 
scrub pine" (Blatchley, 1910, p. 791). Blanchard's data 
was derived from specimens actually cut from white pine 
during July and August. 

Chrysobothris blanchardi was obtained only from the 
branches and tops of larch. The eggs are laid under the 
bark of weakened, dying or recently dead trees. The larval 
burrows are rather long and flattened in cross section, but 
considerably narrower than in several of the sister species, 
including those mentioned later. Although there is much 
variation in the burrows, yet it is usually true that at first 
the larval mine is likely to be longitudinal and nearly 
straight, or at most only wavy in its course, while that made 
by the nearly full-grown larva later is likely to be very tor- 
tuous, often crossing and recrossing its own former path. 
(Figs. 23, 24.) The entire burrow is tightly packed with 
frass and that derived from the bark and from the sapwood 
is often so arranged as to form alternate dark and light 
strise, as shown in Fig. 25, The material for this is derived 
by the larva alternatingly excavating from the bark and from 
the sapwood, and this is arranged to form the curved strise by 
the abdomen of the borer, which is habitually curved, the 
loop being pressed against the packed frass to afford leverage 
while the larva is rasping off the woody fibres. Pupation 
takes place in a shallow chamber extending longitudinally 
with the wood fibre and lying just under the surface of the 



82 College of Forestry 

sapwood. The adult leaves the pupal chamber through the 
same opening as that through which the larva gained access, 
and on reaching the level of the bark, there constructs an 
oval emergence hole. Two years are required for the com- 
pletion of the life history. 

The associated insects are the same as for Neoclytus 
longipes given previously and it seems unnecessary to repeat 
the list here. 

Chrysobothris sex-signata Say. 

Chrysohothris sex-signata, according to Horn (1886, 
p. 112), " Occurs from ISTew York to Virginia, westward to 
ISTebraska and Indian Territory." Blanchard (1889, p. 31) 
records it as occurring in New England but as " rather 
scarce." Blatchley (1910, p. Y91) also speaks of it as scarce 
in Indiana, although he lists it from five countries. 

JSTo record of this insect actually having been bred from a 
conifer was found, but Blanchard (1889, p. 31) has beaten 
it from pitch pine. Chittenden (1889, p. 219) records it as 
having been " cut from a beech tree in which it had bred." 
iSmith (1909, p. 293) reports it " on beech, birch and chest- 
nut." This species, like many others of the same genus — 
and indeed many other genera of buprestids — doubtless 
breeds indiscriminately in a large number of trees, both 
broad-leaved and coniferous. The authors have not only 
obtained a number of specimens from larch, but also have 
bred large numbers from hickory. 

The female chooses the same sort of material in which to 
deposit her eggs as does C. hla7icliardi. The liurrow made 
by the larva is quite variable. Sometimes it is only mod- 
erately coiled as in Fig. 26, while in other cases it is so 
tortuous that it is impossible to trace its course throughout 
its entire length, owing to the fact that the larva crosses and 
recrosses its old track. The burrows, when they can l^e 
traced, are usually readily distinguishable from those of 
C. hlanchardi by their l)eing actually broader and relatively 
shallower. The length of tlie Inirrows of C. sex-signata is 
more often less than those of the sister species, but this varies 



Insects Bred from American Larch 83 

somewhat, dependent both upon the ultimate size of the indi- 
vidual making the burrow and upon the width of the burrow 
itself. In C. sex-signata the gallery leading to the pupal 
chamber is also noticeably wider — i. e., is a flatter oval in 
cross section — than in the other species. The general char- 
acter of the burrow of this species is well shown in Fig. 26, 
although it should perhaps be stated that it is rarely that the 
entire course of the larval mine is so readily to be seen as it is 
there. This species requires two years for its life history, 
the adults emerging in midsummer. Our record includes 
specimens emerging nearly daily from June 21 to July 30. 
The associated insects are the same as for Neoclytus lon- 
gipes. 

Chrysobothris dentipes Germ. 

Clirysohothris dentipes seems to occur throughout the 
greater part of southern Canada and the timbered areas of 
the United States. The earliest record of a host plant for 
this flat-head is that of Harris (1862, p. 42), who says that it 
'' inhabits the trunks of oaks". This is confirmed by Fitch 
(1859, p. 793) and by Packard (1890, p. 60). Blanchard 
(1889, p. 31) and Crittenden (1889, p. 219) record it as 
common on pine and the latter concludes that '' it is doubtful 
if it breeds in any but coniferous trees". This latter view 
seems to us not at all well taken, on account of the definite 
records from oak and in view of the well known fact that 
several species of this genus attack a large number of both 
coniferous and broad-leaved trees and even shrubs with little 
apparent preference. Packard (1890, p. 680) has taken 
dead adults of this species from beneath the bark of pine 
and Felt (1906, p. 657) records it from hard pine. It has 
been bred in our laboratory not only from larch but also from 
white pine. 

In depositing their eggs the adults of, C. dentipes choose 
much the same sort of material as do the other species al- 
ready treated. They prefer the thin barked portions of larch 
and pine which is either weakened, dying or recently killed. 
Pine " slash " affords excellent conditions and they will 



84 College of Forestry 

breed in such material in immense numbers. Larvse were 
also numerous in pine limbs which had been suppressed by 
'shading and in the upper part of pines weakened by 
shading and killed by the attacks of other insects such as 
Dendroctonus valens and Ijps longidens.^' 

The eggs were laid in larch that was not yet entirely dead, 
as was indicated by the fact that in some cases the early por- 
tions of the burrows are filled with f rass saturated with pitch. 
This frass is arranged and packed by the abdomen to form 
the curved striae mentioned in connection with C. hlanchardi 
and evidence to indicate that the pitch was successfully 
manipulated by the larva is furnished by curved bands of 
pitchy frass alternating with other bands devoid of excessive 
resin. Still other cases were observed of burrows which had 
been made by this species several years before the death of 
the limb. These had been partly filled with pitchy frass and 
had thus been, to some extent, preserved from decay. The 
bark, however, had later been removed by some unknown 
cause and the burrows partly overgrown by the attempt at 
repair on the part of the tree. 

The burrows made by the larvae of C. dentipes are broader 
than those of any of the other species of flat-head borers in 
larch — fully twice as broad on an average as are those of 
C. hlanchardi. The course varies greatly. In one case 
in larch the burrow is longitudinal and nearly straight 
throughout the greater part of its length of nearly twenty 
inches (495 mm.) — this doubtless being due to the larva 
having met no obstructions in its course. In another case a 
piece of pine top nine inches long and slightly more than two 
inches in diameter contained fifteen larvse. The burrows in 
this piece are very tortuous (Fig. 27), often crossing and 
recrossing each other, so as to make it impossible to trace any 
particular one in its entirety. 

This insect requires two years for the completion of its 
life history. The larvae on reaching full growth burrow 

* For the information relative to C. dentipes in white pine we are 
indebted to the notes of Mr. A. J. MacNab, a former graduate student 
in the department. 



Insects Bred from American Larch 85 

diagonally into the sapwood (either of pine or of larch), and 
often continue their burrows for a consideral)le distance 
through the sapwood parallel to the surface. Usually in 
larch the larva, after it has burrowed several centimeters, 
carries the mine up to the surface of the sapwood, then 
retreats down into it and pupates. The adult on arising 
emerges by continuing the burrow made by the larva up 
through the bark. In pine, where the sapwood is much 
softer and more readily worked, the larva often burrows for 
a considerable distance before it pupates. In one case the 
burrow was followed in its entirety for a distance of 13 cm. 
between the point of entrance and the emergence hole of 
the adult — the pupal chamber being 10.5 cm. from the 
entrance hole of the larva. All of the burrow except the 
pupation chamber is filled with frass. It will be apparent 
that the burrows of C. dentipes can be readily distinguished 
from those of other flat-headed larvse occurring in larch by 
the facts just mentioned — i. e., that the larva typically 
burrows through the sapwood for some distance before 
pupating, and that the adult does not follow the larval bur- 
row back to the bark but constructs a new exit in order to 
reach the outside. 

Insects associated with C. dentipes in larch are the same 
as those listed for Neoclytus longipes. Where insects are 
excessively numerous, as shown in Fig. 27, whether they are 
of the same or of different species, it is of course apparent 
that they are injurious to each other, to such a degree as they 
limit the food available for all. 

Anthaxia quercata Fabr. 

Anthaxia quercata is reported by Horn (1882, p. 110) as 
being distributed throughout the Middle, Southern and 
Western States and California. This includes the distri- 
bution of A. cyanella, which is the female of the same 
species. This species has been bred by Chittenden (1889, 
p. 219) from chestnut twigs and he has likewise taken the 
male from the leaves of chestnut and chestnut oak. Blanch- 
ard (1889, p. 31) reports it as common in oak shrubs; Felt 



86 College of Forestry 

(1906, p. 578) has taken it from the leaves of scrub oak, 
and Smith (1909, p. 293) reports the '' hirva iu grape and 
chestnut.'' We tind no previous record of its having been 
obtained from a coniferous species. 

The females of this small buprestid dej)osit their eggs in 
dying or recently killed larch — and other trees — choosing 
limbs of a diameter of from three- fourths of an inch to one 
and a half inches. The larval burrows, in common with 
those of most flatheads, are considerably broader than they 
are deep. They are constructed immediately under the bark, 
grooving both bark and sapwood, but nearly all of their 
depth is excavated from the sapwood. The course of their 
burrow is at first longitudinal and is not excessively tortuous. 
(Fig. 22.) The width of the burrow at the start is about 
one millimeter and by the end of the first year this has 
about doubled. The burrow made ])y the larva during its 
second season is much more varial^le both in diameter and 
in direction. The final result may be a very tortuous burrow 
which rej^eatedly crosses and recrosses its own course, or it 
may consist of an irregular broad area, as shown in Fig. 22. 
The entire larval mine is tightly packed with frass, and that 
derived from the bark and from the sapwood is usually so 
arranged as to form alternate dark and light bands or strise 
just as in C. hlancJiardi. 

The larva completes its growth during the second summer 
and then constructs a shallow jjupation chamber in the outer 
sapwood. This extends diagonally do\Yn into the wood for 
a distance of from 6 to 9 mm. The larva apparently pupates 
with its head toward the larval burrow, egress from the 
pupal chamber being obtained through the larval entrance. 
Exit of the larva through the bark is made through a small 
oval (sometimes nearly semi-circular) opening, which can 
be readily distinguished from those of the other buprestids 
by its small diameter. 

Insects associated with Anthaxia quercata form the typical 
limb association and comprise Keoclytus longipes and the 
species previously listed as bred from the same source. 



Insects Bred from American Larch 87 

Serropalpus barbatus* Schall {striatus Hell.) 

According to Hamilton (1889, p. 152; 1894 a, p. 33) 
Serropalpus barhatus is distributed throiigliont Central and 
K^orthern Europe, Siberia and the Northern part of North 
America, extending through the Rocky Mountains as far as 
'New Mexico. In the East it occurs at least as far south as 
West Virginia (Hopkins, 1893, p. 203). 

The European hosts recorded for this melandryid by 
Judeich and Nitsche (2895, p. 1304) are silver hr, Scotch 
fir and pine. In America Hopkins has taken it from spruce 
(1893, p. 203) and from balsam (Felt, 190G, p. 671), and 
Smith (1909, p. 365) reports having taken it " at light and 
from dry fungus." The senior author has cut larvse, pupae 
and adults from the wood of balsam, sj)ruce and hemlock in 
the vicinity of Cranberry Lake, N, Y. We bred numerous 
specimens from larch, which tree apparently has not pre- 
viously been recorded as a host. 

^S*. barhatus was first mentioned in forestry literature by 
Ratzeburg in 1863, but its work was not adequately described 
and illustrated until Erne gave a rather complete account 
of its habits in 1892. According to the latter's ol)servations 
(Judeich and Nitsche, 1895, p. 1804), the adult is nocturnal 
in its habits and at this time all of its activities are carried 
on. In the daytime it conceals itself in the moss on the 
trees and in the ground cover. Erne believed that the life 
history required three years, while Wachtel (also cited by 
Judeich and Nitsche) states that the life cycle is completed 
in two years. ' Our own observations show that under the 
climatic conditions of Central New York two years is suf- 
ficient. We have, however, already pointed out the danger 
in making dogmatic statements regarding duration of life 
history, as such processes are subject to much variation even 
in the same general locality, being dependent upon the actual 
temperature and moisture conditions existing in the particu- 
lar tree or other material infested. 

* Descriptions of the adult, larva and pupa of this species are given by 
Judeich and Nitsche (1895, p. 1303). 



88 College of Forestry 

8. harbatus in ovipositing in larch chooses either trees 
which are dying or which have recently died, or living trees 
from which part of the bark has been peeled (this latter 
being in line with its common name of " blazed tree borer "). 
Occasionally oviposition occurs in living trees — most often 
in injured or dead parts of the bark. In several cases adults 
emerged from recently dead larch the same year as Poly- 
graphus and Eccoptogaster — indicating that it must have 
entered this material a year earlier than did the scolytids, 
while the trees were still alive. Usually only the lower trunk 
is attact, but several specimens have been bred from the 
trunk up among the limbs as much as thirty feet from the 
ground. 

The larval stage of 8. harbatus is spent nearly entirely in 
the sapwood. As soon as they are hatched, the larvae bur- 
rows from the bark into the sapwood and continues mining 
this part of the tree for two seasons. The larval burrows 
are very irregular in their course, winding this way and 
that and showing no discoverable pattern. It is noticeable, 
however, that a greater part of the length of the burrow is 
in the soft spring wood and it will often extend for several 
inches, either longitudinally, circumferentially or diagonally, 
without leaving a single ring of growth. The burrow is oval 
in cross section, the long diameter, which is about twice the 
shorter diameter, being tangential, i. e., confined to one layer 
of "spring wood." The entire larval mine is packed full of 
a very fine dust-like frass. 

Before transforming to the pupa the burrow is extended 
by the full-grown larva, which reaches a length of 25 mm. 
to a level not more than a half inch from the bark and a 
slightly enlarged chamber is here constructed parallel to the 
surface of the sapwood. However, before transforming, the 
burrow is extended to the surface of the sapwood, so that 
the adult may emerge without having to bore through the 
wood. Field notes of the senior author, dated Cranberry 
Lake, June 10, 1915, read as follows: "Numerous adult 
beetle and two larvse taken from sapwood of a small dead 
hemlock. Adults were taken from chambers extending 



Insects Bred from American Larch 89 

inward one-half inch and thence either downward or to the 
side about one inch. These chambers had been opened to 
the inner bark, but not through this, and the openings 
through the surface of the sapwood were not large enough 
for passage of beetle. When removed the beetles were quite 
lively and active." The beetle emerges through a circular 
hole in the bark. Our records of emergence outdoors extend 
from June 5 to August 3, as follows: 1916, June 6, 7, 8, 
13, 15 ; July 1, 6 ; August 3 ; 1917, June 5, 19, and July 12. 
In the Adirondacks the senior author took adults from hem- 
lock wood June 10, 1915, and balsam June 26, 1915. Pupse 
were cut both from spruce and balsam June 27, 1915. Larva? 
were obtained from hemlock June 10 and from spruce June 
27, 1915. Individuals of S. harhatus differ greatly in size, 
specimens we have varying from 6.5 mm. to 18 mm. 

Insects associated with Serroplapus harhatus include the 
scolytids — Dendroctonus simplex, Polygraphus rufipeimis. 
Eccoptogaster picece, Cryptiirgus pu-sillus; the cerambycids 
— Asemum moestum, Monoluvimnus scutellatus and Phyma- 
todes dimidiatus ; the buprestid — Melanophila fulvoguttata, 
and the two siricids — Urocerus alhicornis and Sirex abhotii. 
Kone of these habitually precede 8. harhatus in the wood, 
but occasionally D. simplex and A. moestum may attack the 
tree first. Most often, perhaps, the melandryid is the first 
insect to enter the living tree — entrance for the egg being 
gained through some mechanical injury such as a blaze or 
other abrasion. In weakened trees Serropalpus is likely to 
deposit its eggs at about the same time as A. moestum and 
before any of the other insects listed above. In such cases 
the adults of both of these two-year forms emerge at the 
same time as do those of D. simplex, P. rufipennis, E. picece, 
P. dimidicatus, U. alhicornis and S. ahhotii, all of which 
are one-year forms entering the tree a year later. In other 
cases all of the associates listed above enter the tree during 
the same season and the one-year forms will then have been 
gone an entire year before the emergence of 8. harhatus and 
the other two-year forms — A . moestum, M. scutellatus and 
M. fulvoguttata. 



90 College of Forestry 

The presence of S. harhatus and of other wood-horing 
forms in a tree serves to prepare the wood for other insects 
which otherwise could net utilize it, or at least would not be 
likely to utilize it. This was especially noticeable in Tree V, 
which had been partially peeled a number of years before 
its final death. The presence of the burrows in the wood not 
only affords the insects mechanical entrance to the wood, but 
also so promotes decay as to make it fit material for such 
forms as Adelocera hrevicornis, Tenehrio tenehriodes, Dry- 
ophthorus ainericanus and Stenoscelis hrevis to inhabit. 
After decay has started any or all of these forms may enter 
the exposed wood and the two latter at least may continue to 
breed in it for several generations. 

Phyllohaenus dislocatus is the only predator bred from the 
same material as S. harhatus. On account of the character 
of the burrows of the latter and because of their being filled 
with fine sawdust it is not likely that any close relation exists 
between these two forms. iSTo evidence of parasites upon 
S. harhatus was found. 

Urocerus albicornis Fabr. 
(Det. by S. A. Rohwer) 

According to Bradley (1913, p. 19) the geographical range 
of Urocerus alhicornis extends "From British Columbia, 
Northern Ontario, Xova Scotia and Newfoundland, south to 
Pennsylvania, Washington and Xorthern Idaho." Hopkins 
(1893 a, p. 215) reports it also from West Virginia. This 
species was recorded by Packard (1890, p. 733) as attacking 
pine. Later Hopkins (1893, p. 215) found the larvje in the 
sapwood and heartwood of injured and dying hemlocks, 
while Felt (1906, p. 667) mentions spruce and fir as host 
trees. The senior author has taken it from the wood of 
spruce, fir and hemlock in the Adiroudacks. 

The adult female of U. alhicornis prefers freshly killed 
wood in which to oviposit. This is very apparent in the 
Adirondacks, where females of this horntail are often seen 
about recently felled spruce and fir. On one occasion the 



Insects Bred from American Larch 91 

senior author observed three specimens at one time hovering 
about spruce recently felled and stripped for pulp wood and 
which was at that time being piled upon a skidway. 

Entomological literature contains numerous mention of 
this insect as a wood borer, but apparently no data is avail- 
able as regards length of larval and pupal life history. Our 
data, while not absolutely conclusive, shows that usually the 
life history is completed in one year. This, however, is 
doubtless subject to considerable variation, dependent not 
only upon the general climatic conditions but also upon the 
exact individual conditions in each case. 

The eggs are deposited by the females in the bark of 
dying or recently felled coniferous trees. Preference is 
shown for recently felled trees, but failing these, trees dying 
or even dead are used for ovipositing. The larvse on hatch- 
ing bore directly into the wood, in which they construct their 
mines throughout their entire larval existence. These bur- 
rows run in all directions through the wood and are closely 
packed with a very fine dust like frass. In general they are 
very much like the mines of 8. harhatus, but can be dis- 
tinguished by the fact that they are nearly exactly circular in 
cross section, while those made by the melandryid are oval. 

Adults of this siricid emerged in our outdoor breeding 
cages during June and July. In all, twelve specimens were 
obtained — comprising two females and ten males. Of 
these one male and one female were obtained in July, 1916, 
from Tree II. The other female and the nine males were 
obtained from the lower, middle and upper trunk regions of 
Tree X. Mr. Rohwer of the Bureau of Entomology in iden- 
tifying these specimens makes the following statement 
regarding the males: "At present there are no characters 
known which definitely separate the male of Urocerus albi- 
cornis Fabr. from the male of Urocerus fl,avicornis Fabr. 
and it is impossible to be positive as to the above determina- 
tion." However, the fact that the males were bred from the 
same material as the known females of U. albicornis and 
emerged at about the same time would make the presumption 
very strong that they belong to this species. These specimens 



92 College of Forestry 

show considerable variation not only in size but in coloration. 
In size the five males still in our possession vary from 12 mm. 
to 18 mm. The differences in coloration, which are quite 
striking, consist in a variation in the relative amount of 
yellow upon the antennae, abdomen and legs. 

Borers associated with U. alhicornis are Polygraphus rufi- 
pennis, Eccoptogaster picew, Phymatodes diinidiatuSj, Serro- 
palpus harhatus and Sirex ahhotii. As U. alhicornis, which 
is typically a one-year form, attacks weakened, dying or veiy 
recently killed trees, its life history in the wood coincides 
with or overlaps that of each of these forais. The two 
scolytids usually enter the bark rather early in the same 
season, and are therefore likely to have been established a 
month or more before the eggs of the siricid are laid. 
P. diinidiatus, also a one-year form, probably enters the tree 
about the same time as the Urocerus, but as its burrows are 
entirely in the bark, the two forms have no direct or very 
definite relations. 8. harhatus and Sirex ahhotii are both 
wood-boring forms similar to U. alhicornis, but the relations 
are never likely to be close. No case was observed where 
these various wood-eating larvae were present in such number 
as seriously to interfere with each other's chances of obtain- 
ing food. The occupancy of the wood by the larvae of Sirex 
ahhotii and of U. alhicornis coincides nearly exactly. >S'er- 
ropalpus, however, is a two-year form and its larvae may have 
lived in the sapwood an entire year before the advent of the 
other borers and during this time may have performed a 
very important function in overcoming the resistance of a 
weakened tree. 

While a number of parasites were bred from the same 
material as U. alhicornis, no evidence of any close relation 
between them and the siricid was found, though many bur- 
rows were examined for cocoons. The predator Phyllohaemis 
dislocatus was obtained from the same material, but no 
reasons for believing it predaceous upon U. alhicornis were 
found. 



Insects Bred from American Larch 93 

Sirex abbotii Kirby. 

(Det. by S. A. Rohwer) 

The distribution of Sirex ahhotii is given by Bradley 
(1913, p. 13) as Georgia, ISTo record of host trees has been 
found in the literature. It is very likely that this species 
will be found to breed in about the same trees as 8. cyaneus, 
which occurs in spruce and fir, but which perhaps has a more 
northern range. 

All our specimens of this siricid were bred from larch 
material derived from Tree X, the same tree from which 
most of the specimens of U. albicornis were obtained. The 
specimens of *S^, ahhotii, however, emerged from the lower 
and middle trunk region only. Otherwise the habits seem 
to be practically identical with those of the other siricid, A 
total of thirteen specimens were obtained, ten of these being 
males and three females. Mr. S. A. Rohwer, who in iden- 
tifying them has examined one of the females and a number 
of the males, says : " The above record for a female of Sirex 
ahhotii Kirby is the first association of a female with this 
species. The female is very close to S. cyaneus Fabr. and 
may be under that name in collections." The specimens 
emerged in our cages during June and July (June 9 ; July 6, 
12, 13, 16, 17, 18), 

Sirex ahhotii belongs to the same association as U. alhi- 
cornis and bears the same relations with its associates as does 
the other siricid. 



Tenebrio tenebriodes B 



eaur. 



Tenehrio tenehriodes is probably distributed throughout 
the entire northeastern part of the country, as it has been 
reported from Pennsylvania (Hamilton, 1895, p. 341), ISTew 
York (Felt, 1906, p. 493) New Jersey (Smith, 1909, 
p. 359) and Indiana (Blatchley, 1910, p. 1251). Further 
than the fact that this insect is usually found under decay- 
ing bark or in other similar locations very little is known 
regarding its habits. Felt (1906, p. 493) records it " under 
decaying willow, butternut and basswood bark in early 



94 College of Forestry 

spring." Smith (1909, p. 359) has taken it "Under bark 
of trees, among rubbish in barns and outbuildings." Blatch- 
ley (1910, p. 1251) speaks of it as " Common beneath bark." 

It will be seen from the above references that no definite 
statements regarding the breeding habits or food habits of 
this beetle was found in the literature. It apparently is not 
known whether it breeds under bark or whether it merely 
hibernates there. The fact that the adults are taken con- 
stantly in the spring or early summer from under bark does 
not afford evidence to suj^port either view. Nor does the 
fact that it has been taken from a variety of different species 
of tree offer any real evidence — it being a well-known fact 
that insect inhabitants of wood well along in decay, usually 
show little preference for any particular species. The evi- 
dence we have to offer is quite scant and inconclusive, but 
it points toward T. tenehriodes being a true inhabitant of 
decaying wood throughout its life. The material (Tree V) 
was confined in breeding cages late in April and the adult 
beetle did not appear in the cage until July 7. Had it been 
merely hibernating in the wood, it would likely have been 
found earlier. 

The material from which T. tenehriodes was derived con- 
sisted of the decayed heartwood of Tree V which had been 
peeled many years ago (Figs. 29, 30). This exposed wood 
had at one time apparently served as the breeding place of 
S. harhatus which, however, had emerged a number of years 
before the material was confined in the cage. Two other 
insects were taken from this wood — Adelocera hrevicornis 
(taken from the wood in the field April 28) and Dryoph- 
thorus americanus (July 3). A. moestmn, P. .dimidiatus 
and 8. harhatus were bred from this same tree but emerged 
from the sounder more recently killed portion. 

Adelocera brevicornis LeConte 

Adelocera hrevicornis is perhaps distributed over the 
greater part of eastern United States and Canada. Adams 
(1909, p. 196) gives the geographical range as Ottawa, 
Canada; Michigan; Lake Superior. Smith (1909, p. 284) 



Insects Bred from American Larch 95 

reports it from The Palisades, ]^. J. Blatchley (1910, 
p. 715) records that this sjjecies " is known from Michigan 
and Wisconsin." 

The only reference to the habits we have been able to find 
is the general statement regarding the genus by Smith (loc. 
cit.), that all the species occur under dead bark. We ob- 
tained but one specimen from larch and this was taken 
from punky wood April 28. It is believed that A. hrevicomis 
breeds in decaying wood and under decaying bark, but we 
can offer no real evidence for this view. 

The insects associated in the decayed wood are Tenehrio 
tenehriodes and Dryophthorus amejicanus. If A. hrevicomis 
breeds in such surroundings it would also often be associated 
with Stenoscelis brevis. The recently killed part of the same 
tree contained Phymatodes dimidiatus, Asemum moestum 
and Serropalpus harhatus. 

Phyllobaenus dislocatus Say. 

Phyllohcenus dislocatus has been reported from various 
parts of the United States: Hopkins (1893, p. 187), West 
Virginia; Hamilton (1895, p. 335), Pennsylvania; Felt 
(1906, p. 503), New York; Sehaffer (1908, p. 127), Ari- 
zona; Wolcott (1909), Wisconsin and Ohio; Smith (1909, 
p. 303), New Jersey; and Blatchley (1910, p. 859), 
Indiana. 

This small clerid has been reported as associated — doubt- 
less in the capacity of a predator — with a large number of 
bark and wood-inhabiting forms derived from a variety 
of different trees. Hopkins (1893, p. 187) states that it 
" Attacks PolygrapJius r'ufi/pennis in Black Spruce and 
PityophtJtorus consimilis in vSumach (Rhus glabra) and 
with Scolytus regulosus in Apple bark." According to Felt 
(1906, p. 449), LeConte reared it from hickory twigs con- 
taining Clwatnesus hicorice. Felt (1906, p. 503) reared it 
from hickory limbs infested w^ith ChrysobotJiris femorata, 
and Magdalis olyra. Blackman (1915, p. 54) records having 
bred P. dislocatus from limbs of pine containing Pityogenes 
liopkinsi and no other borer, and Chapin (1917, p. 29) 



96 College of Forestry 

obtained several specimens from twigs of Rhus glabra asso- 
ciated with the cerambycids Liopus fascicularis, Harr. and 
Psenocerus supernotatus Say and the scolytid PityophtJiorus 
conslmilus Lee. 

From the fact that P. dislocatus is constantly found in the 
burrow of a great variety of other insects, there can be little 
doubt that it is predaceous upon a large number of species. 
In larch it was bred from practically every lot of material 
placed in the breeding cages and therefore a list of probable 
associates in larch would include practically all of the forms 
bred from larch, including parasites and other predators as 
well as the true borers (see table on p. 38). It is indeed 
possible that this elerid may on occasion be predaceous upon 
all of these various forms. Even such forms as the larvae 
of Monohammus scutellatus, which when well grown would 
conceivably be very well able to defend themselves would, 
when small, be comparatively helpless if attacked by an 
active, full-grown larva or by an adult of P. dislocatus. 
Furthermore, on account of its burrow being open from the 
time the larva is hatched, this round head would seem to be 
particularly subject to attack by predators. 

Perhaps the greatest dijfficulty in the way of P. dislocatus 
being freely predaceous upon all of these insects, lies in the 
fact that typically the burrows of all of the flatheaded borers 
and most of the roundheaded borers in larch are entirely 
devoid of opening to the outside (except accidental openings) 
and in the further fact that the larval burrows are filled with 
more or less firmly packed frass. Occasionally, free access 
to such larval burrows may be had, however, through the 
egg-galleries of associated scolytids, at places where these 
latter passageways are crossed by the burrows of the larger 
larvse. 

However, we are certain that in most cases P. dislocatus 
preys principally upon scolytids. It is by no means unusual, 
on opening a burrow of P. rufipennis or other scolytid, to 
find the original inhabitants all dead and the burrow uncom- 
pleted. In such cases, the remains are likely to consist of 
the mere external shell of the scolytid, all of the soft parts 



Insects Bred from American Larch 97 

having been devoured by the predator. Most usually the 
opening through the hard outer shell is through the posterior 
abdomen, this apparently being the most vulnerable point 
of attack. In one instance on opening the burrow a larva 
of P. dislocatus was discovered with its head thrust into the 
body of a recently dead P. rufipennis as far as the prothorax. 
When the clerid larva was removed the body of the scolytid 
showed fresh signs of having been eaten. There is also good 
evidence to show that both larvae and adults feed quite readily 
on the dead and dried bodies of scolytids and even upon those 
which must be well along in decay. Thus this clerid acts as 
a scavenger as well as a predator. 

The scolytids with which P. dislocatus have been found 
constantly associated in larch are Polygraphus rufipennis, 
Dendroctonus simplex, Eccoptogaster piceoe and Crypturgus 
pusiUus. It was actually taken from under the bark among 
the burrows of each of these scolytids and there can be little 
doubt that it acts in the capacity of a predator and scavenger 
in the burrows of all of these forms. It is believed that as 
a predator P. dislocatus (and other clerids) most often 
attack the adults rather than the larvae of scolytids. The 
larva or adult of the predator in order to reach the scolytid 
larva would either have to construct a new burrow of its own 
through the bark or would have to clear the larval burrow 
of frass and enlarge it. On the other hand the adults are 
quite accessible. When in the brood-burrow, the predator 
can reach them readily through the entrance to the nuptial 
chamber, while the young adults for a considerable time 
before emergence are readily accessible through the " ventila- 
tion openings " in their feeding galleries. 

Cymatodera bicolor Say. 

Cymatodera hicolor was described from a specimen from 
Arkansas and Horn (1888, p. 224) gives its range as " The 
Middle and Gulf States." It has later been reported by 
Wickham (1895, p. 249) from Ontario and Quebec, by 
Smith (1909, p. 302) from New Jersey, by Leng (1908, 

4 



98 College of Forestry 

p. 27) from Arizona and (1910, p. 77) from Georgia, and 
by Blatchley (1910, p. 850) from Indiana. 

The most definite statement regarding the habits of this 
clerid is furnished by Hopkins (1893a, p. 185) when he lists 
it as predaceons and states that it occurs with Phloeoshius 
dentatus in cedar bark. In larch it was found associated 
with the borers Polygraphus rufipennis, Phymatodes dimi- 
diatiis and Leptostylus sex-guttatus, with the clerid Pliyllo- 
hcenus dislocatus and with the parasites Bhyssa lineolata, 
Pseudorhyssa sp., Eurytoma sp., and several undescribed 
species of Doryctes. C. bicolor may be predaceous upon any 
of these but is more likely to feed habitually upon the scoly- 
tid P. rufipermis. It probably also acts as a scavenger in 
obtaining part of its food. 

Podabrus diadema Fab. 

The geographical range of Podabrus diadema is given by 
Adams (1909, p. 199) as Ottawa, Canada; Mt. Washing- 
ton, N. H. ; Vermont ; New York ; jSTew Jersey ; Western 
Pennsylvania; Michigan; Wisconsin; Iowa. Smith (1909, 
p. 299) reports it from New Jersey. 

Nothing regarding the habits of this lampyrid was found 
in the literature but we believe that it acts as a predator 
and as a scavenger. Regarding the sister species P. regu- 
losus Blatchley (1900, p. 830) states that it "Occurs on 
the leaves and flowers of various shrubs and herbs. One 
was noted feeding on a winged plant louse." 

Only one specimen of this beetle was bred from larch. 
It emerged on June 15, 1916, from a section of the trunk 
of larch about thirty feet from the ground, infested heavily 
with the brood of P. rufipennis. The only other insects bred 
from this lot aside from the scolytid already mentioned were 
P. dislocatus and a small undetermined chalcid. It is likely 
that P. diadema inhabits the burrows of Polygraphus. 



Insects Bred from American Larch 99 

Rhyssa lineolata Kirby. 
(Det. by S. A. Eohwer) 

According to Merrill (1915, p. 147) the geographical 
range of Rhyssa {persuasoria) lineolata is very wide, extend- 
ing " Through Europe to Canada and the United States in 
the West, and the Himalayas in the East." Merrill {loc. 
cit., pp. 14-1—14:7) has reviewed at some length what is known 
regarding the habits of this species and it seems undesirable 
to repeat this here. It has been reported as parasitic upon 
Sirex spectrum, Sirex (Urocerus) cyaneus and Monoham- 
mus, while other species occurring in Europe are parasitic 
upon several species of Xyphydria. 

In our larch material there can be no doubt that R. lineo- 
lata is parasitic upon Phymatodes dimidiatus. The reasons 
for this statement have been cited on p. 32 and seem conclu- 
sive. The fact that cocoons large enough to have served the 
pupa of R. lineolata and Pseudorhyssa sp. occurred only in 
the burrows of P. dimidatus and that no cocoons of any sort 
were discoverable in the mines of S. harhatus, the only other 
insect common to the three lots of material would seem to 
be conclusive. Of the three lots from which this parasite 
was bred only one gave rise to any siricids, U. alhicornis and 
S. ahbotii being obtained from this lot, and an investigation 
of their burrows showed the entire absence of parasitic 
cocoons. 

While we cannot state too strongly our certainty that R. 
lineolata in our material was parasitic upon P. dimidiatus, 
we do not in any sense wish to cast discredit upon observa- 
tions which have shown it to be probably parasitic upon 
quite different insects. Indeed, it is nearly certain that this 
species is parasitic upon many wood and bark-boring forms. 
In fact, the senior author has removed an adult from the 
wood of hemlock where it was associated with adults of 
Urocerus alhicornis and with larvse and pupae almost cer- 
tainly belonging to the same species. As the adult parasite 
which was alive and ready to emerge was removed from a 
burrow similar in all respects to those from which the speci- 



100 College of Forestry 

mens of U. alhicornis were taken there can be little doubt of 
its being parasitic upon this species also. 

In larch the associated insects in addition to Phymatodes 
dimidiatus are, Leptostylus sex-guttatus, Aseinum moestum, 
8eiTopalpus harhcttus, PolygrapJius rufipennis, Eccoptogaster 
piceoB, Urocei'us alhicornis^ Sirex ahhotii, Pliyllohcenus dis- 
locatusj, Cymtodera hicolor, Pseudorhyssa sp., Doryctes, sp., 
a, b, c, Eurytoma sp., Spathius toinici, Spathius sp., and an 
undetermined pteromalid. 

Pseudorhyssa sp. 
(Det. by ti. A. Eohwer) 

Four specimens of this new species of Pseudorhyssa were 
bred from the trunk of Tree III from five to seven feet above 
ground. Of these three specimens were retained by Mr. 
Rohwer and one is in our collection. This species also is 
parasitic upon Pliyinatodes dimidiatus, as was shown by a 
careful study of all of the burrows in the material from 
which it was bred. The adults emerged in the outdoor breed- 
ing cages on May 24 and 25, 

Insects associated with it aside from P. dimidiatus already 
mentioned as its host, include the borers; Leptostylus sex- 
guttatus, Serropalpus barhatus and PolygrapJius rufipennis; 
the predators, Phyllohcenus dislocatus and Cymatodera 
hicolor; and the jiarasites Rhyssa lineolata Eurytoma sp., 
and three species of Doryctes. 

Odontaumerus canadensis Pro v. 
(Det. by S. A. Rohwer) 

No references to this ichneumonid were found in the liter- 
ature examined by us. It was bred from Tree III and was 
associated with Phymatodes dimidiatus, Leptostylus sex- 
guttatus, Serropalpus harhatus and PolygrapJius rufipennis. 
It is most probably parasitic on P. dimidiatus. This ceram- 
bycid had been very numerous in the tree trunk, and cocoons 
of a size which would be made by this parasite, were present 
in its burrow and none of a suitable size were found in any 
others in this lot of material. 



Insects Bred from American Larch 101 

Predators associated include Phyllohcenus dislocatus and 
Cymatodera bicolor. The parasites present in the same 
material were Rhyssa lineolata, Pseudorhyssa sp., Eurytomu 
sp., and three species of Doryctes. 

, Odontaulacus bilobatus Prov. 
(Det. by S. A. Rohwer) 

According to Bradley (1908, p. 124) this ensign-fly has 
been taken in Quebec and West Virginia. ISTo reference to 
the host of this species was found in the literature, but Plop- 
kins (1893, p. 216) states that the sister species 0. abdomi- 
nalis was bred from hemlock infested with Melanophila 
fidvo guttata. 

In larch 0. hilohatus was associated with the buprestids, 
Melanophila fidvoguttata, Chrysohothris blanchardi, C. den- 
tipes, C. sex-signata and Anthaxia quercata; the ceramby- 
cids, Pogonocherus mixtus, Neoclytus longipes, Leptostylus 
sex-guttatus ; the scolytids, Polygraphus mfipennis and 
Eccoptogaster picece; the clerid Phyllobcenus dislocatus ; the 
hymenopterus parasites, Atoreutus astigmuSj, S pathius tomici, 
Phasgonophora sp., Cheiropachus sp., arid Heterospilus sp., 
and the fly Pollenia rudis. Of these the two scolytids, P. rufi- 
pennis and E. picece; and the parasites S pathius tomici, 
Heterospilus sp. and Cheiropachus sp., emerged the first year 
while the others and 0. bilobatus were associated throughout 
two years. Specimens of P. dislocatus were taken from these 
limbs of larch both seasons. Of the associated borers it is 
most likely that either C. blanchardi, M. fulvoguttata or P. 
mixtus acted as host for this parasite, although it is possible 
that the host may "have been one of the other flat-headed or 
round-headed borers. 

Spathius tomici Ashm. 
(Det. by S. A. Rohwer) 

This small bracomid has been reported as parasitic upon 
Dryocoetes [autographusi americanus Hopkins in spruce 
bark by Hopkins (1893, p. 145) and upon Pityogenes 



102 College of Forestry 

punctipennis Lee. [Tomicus balsameus Lee] by Felt (1906, 
p. 379). 

S. tomici was bred from several lots of larch material and 
was associated with the scolytids, Dendroctonus simplex, 
Polygraphus rufipennis and Eccoptogaster picece. There can 
be little doubt that it may be parasitic upon. the larvae of 
any or all of these small beetles. Cocoons which from their 
size probably gave rise to this small parasite were found in 
the larval burrows of both P. rufipennis and E. picece, but 
were especially numerous in those of the former, and speci- 
mens were bred from other lots of material containing no 
other scolytid than P. rufipennis. The clerid Phyllohcenus 
dislocatus and the parasite Phasgonophora sp., Cheiropachus 
sp., Heterospilus sp., Atoreutus astigmus and Odontaulacus 
hilohatus were also bred from the same materials as were a 
number of cerambycids and buprestids. 

Spathius sp. 
(Det. by S. A. Rohwer) 

An unidentified species of Spathius was bred from the 
upper part of the trunk of Tree X in considerable numbers. 
In this material it was associated with the scolytids, Poly- 
graphus rufipennis and Eccoptogaster, picece; the ceramby- 
cids Phymatodes diniidiatus ; the melandrycid, Serropalpus 
harhatusj and the siricid Urocerus alhicornis. It is undoubt- 
edly parasitic upon one or both of the scolytids mentioned. 

The predator Phyllohcenus dislocatus; the parasitic 
hymenoptera Spathius tomici, Rhyssa lineolata, Doryctes 
sp., Spintherus pulchripennis and an unidentified ptero- 
malid; and the parasitic fly Medeterus sp., were also bred 
from the same material. 

Doryctes sp., a, b, c 
(Det. by S. A. Rohwer) 
Various species of this genus have been recorded as para- 
sitic upon wood-boring larvae (Riley, 1890, p. 350 ; Hopkins, 
1893a, p. 222; Chittenden, 1893, p. 218). A number of 
unidentified specimens, probably representing several new 



Insects Bred from American Larch 103 

species, were bred from larch material. All of them 
were associated with Phymatodes dimidiatus and probably 
emerged from cocoons found in the burrows of this ceram- 
bycid. Oother borers associated were Leptostylus sex- 
guttatus, Serropalpus barbatus, Polygraphus rufipennis, 
Eccoptogaster picece, Urocerus albicornis and 8i7'ex abbotii. 
Other associated insects were Phyllobosnus dislocatus, Cyma- 
iodera bicolor, Rhyssa lineolata, Pseudorhyssa sp., Eurytoma 
sp., Spintherus pulchripennis, Spathius sp., and Odontau- 
merus canadensis. The adults of Doryctes emerged in the 
cage between May 25 and June 5. 

Heterospilus sp. 
(Det. by S. A. Rohwer) 

Species of this genus have been recorded by Ashmead 
(1896, p. 214) as parasitic upon a coleopterous larva (from 
Dr. A. D. Hopkins' records) and by Viereck (1916, p. 238) 
from the galls of Eurosta solidaginis. 

The species here in question came from larch June 2, 
1916. It was bred from limbs of Tree I, emerging at the 
same time as the adults of Polygraphus rufipennis and 
Eccoptogaster picece. It is nearly certainly parasitic upon 
the first of these scolytids and probably upon both of them. 
It was bred from the same material as the various buprestids 
and cerambycids already recorded as characteristic of the 
larch limb association, but emerged a full season ahead of 
these and is therefore nearly certain to be parasitic upon one 
or both of the scolytids mentioned above, which were emerg- 
ing at the same time. Other insects associated and emerging 
at about the same time are the clerid Phyllobcenus dislocatus 
and the two hymenoptera Spathius tomici and Cheiropachus 
sp. Additional parasites emerging a year later are listed in 
the table on page 38. 



104 College of Forestry 

Astoreutus astigmus Ashm. 
(Det. by S. A. Rohwer) 

!No references to this insect were found in the literature 
at hand. We bred but one specimen and it emerged from 
the limbs of Tree I at al)out the same time as Melanophila 
fulvoguttata, Chrysohotliris hlanchardi, C. sex-signata, C. 
dentipes, Anthaxia quercata, Pogonocherus mixfus, Neocly- 
tus longipes, Leptostyhis sex-guttatus and Pliyllohcenus dis- 
locatus. The bark-beetles Polygraphus rufipennis and Eccop- 
togaster picece emerged in some numbers the preceding 
summer and one specimen of the latter emerged the same 
season (being derived, perhaps, from the brood of a second 
generation started in the cages the previous summer). No 
definite statement regarding the exact relations of A. astig- 
mus can be made but it is evident that it is more likely to 
have been parasitic upon one of the two-year forms — 
buprestids or cerambycids. 

Other insects derived from the same material include 
Phasgonophora sp. and Odontaulacus hilohatus, two parasites 
emerging at about the same time, and Cheiropacus sp., 
Heterospilus sp., Spathius tomici and Pollenia rudis which 
emerged a season earlier. 

Spintherus pulchripennis Cwfd. 

(Det. by S. A. Eohwer) 

Hopkins (1893a, p. 227) reports an unidentified sj)ecies 
of this genus as parasitic upon Polygraphus rufipennis in 
spruce bark. Our specimens from larch were obtained from 
one tree only (Tree X) where they were associated with the 
borers — Polygraphus rufipennis, Eccoptogaster picece, Phy- 
matodes dimidiatus, Serropalpus harhatus, Urocerns alhi- 
cornis and Sirex abhotii. This species emerges during the 
early season at the same time as P. rufipennis and E. picece, 
upon one or both of which it is doubtless parasitic. 

The predator Phyllohcenus dislocatus, the hymenoptera 
Spathius tomici, Spathius sp., Rhyssa lineolata, Doryctes 
sp., an unidentified ptermalid and the fly Medeterus were 
also bred from the same lots of material. 



Insects Bred from American Larch 105 

Eurytoma sp. 
(Det. by S. A. Rohwer) 

A number of species of this genus have been found by 
Dr. Hopkins to be parasitic upon the larvse of various scoly- 
tids and other wood and bark-inhabiting insects (Hopkins, 
1893a, p. 324; Ashmead, 1894, pp. 323-327). 

Specimens of this small eurytomid were bred from two 
larch trees (Tree III and Tree IX) where it was associated 
with the borers Polygraphus rufipennis, Phymatodes dimi- 
diatus and Leptostylus sex-guttatus, all of which emerged at 
about the same time. From Tree IX, Neoclytus longipes was 
also bred but it emerged a year later than the parasite. The 
only insect in common between these two lots was P. rufi- 
pennis and its burrows were also the only ones which con- 
tained cocoons from which so small a parasite would be 
likely to come. It is very likely that Eurytoma sp. is a 
parasite upon this small scolytid. The adults emerged in 
the outdoor cages June 5 and July 28, 1916. Other insects 
bred from the same material are Phyllobcenus dislocatus, 
Cymatodera hicolor, Bhyssa Imeolata, Pseudorhyssa sp. and 
several species of Doryctes. 

Phasgonophora sp. 
(Det. by S. A. Rohwer) 

The only reference to the host of a species of Phasgono- 
phora we found is that of Smith (1909, p. 649) in which he 
states that P. sulcata has been bred from Papilio sp. Our 
specimens were bred from larch limbs which had been con- 
fined since the spring of the preceding year. They were 
associated with the following two-year forms and emerged 
at about the same time: Melanophila fulvoguttata, Chryso- 
bothris hlanchardi, C. sex-signata, (J. dentipes, Anthaxia 
quercata, Pogonocherus mixtus and Leptostylus sex-guttatus. 
This species is probably parasitic upon C. hlanchardi and 
possibly upon others of the associated borers as well. 

Other insects bred from the same source include Phyllo- 
bcenus dislocatus, Cheiropachus sp., Atoreutus astigmus, 
Heterospilus sp., Spathius tomici and Pollenia rudis. 



106 College of Forestry 

Cheiropachus sp. 
(Det. by S. A. Rohwer) 

The only reference to a host of a member of this genus 
seems to be that given by Hopkins (1893, p. 148) in which 
he states that C. colon Linn is parasitic upon Scolytus regu- 
losus, the fruit bark beetle. 

We bred our specimens from the limbs of Tree I. The 
parasites emerged in the outdoor cages May 24 and 30, 1916,- 
at about the time when the adults of Polygraphus 7'ufipennis 
and Eccoptogaster picece were emerging from the same 
material. The only other insects from this material during 
the summer of 1916 were PhyUohcenus dlslocatus, Spathius 
tomici and Heterospilus sp., although in the following year 
the typical association characteristics of larch limbs and tops 
emerged. There can be little doubt that this small ptero- 
malid is parasitic upon one or both of the scolytids associated, 
it being nearly certain that E. picece at least is so affected. 

Prosopis sp. 
(Det. by S. A. Rohwer) 

This sm.all black and yellow bee was bred from an outdoor 
cage containing part of the limbs of Tree I on June 5, 1916. 
Members of this genus of which the habits are known, habit- 
ually breed in the pith of various weeds and pithy shrubs. 
Just what the relations of this small bee was to the larch is 
not known, but had it been only hibernating there, it would 
seem as if it would have appeared in the cage considerably 
earlier than it did. The cage contained no punky wood in 
which it might have bred, but several of the sections of limbs 
did contain the abandoned burrows of C. dentipes and other 
borers, and these borings were filled with closely packed 
frass. It will be readily seen that a burrow in the wood 
packed with frass offers conditions somewhat similar to those 
in pith, and it seems possible or even probable that the 
specimen taken had actually bred under such conditions. 

Associated insects emerging at about the same time include 
Polygraphus rufipennisj Eccoptogaster picece, Pliyllohoenus 



hisects Bred from Ainerican Larch 107 

dislocatus, Cheiropachus sp., and Epicallima argenticinctella, 
a small moth. Insects emerging the following season com- 
prise those borers in larch limbs and tops which require two 
years for their development, and the parasites upon these. 

Medeterus sp. 
(Det. by C. T. Greene) 

A number of specimens of this small fly were bred from 
larch wood from a variety of different sources. However, 
this larch material was all similar in that it was infested 
with Polygraphus rufipennis or with both this bark beetle 
and Eccoptogaster picece. Small larvae which may be the 
immature stage of this fly are common in the engravings of 
both these scolytids. Hopkins (1899, pp. 268, 450) con- 
cluded that M. nigripes is a primary parasite of the larvae 
of P. rufipennis. 

Associated insects in addition to the two scolytids already 
mentioned are Pliymatodes dimidiatus, Serropalpus har- 
hatus. U'rocerus alhicornis, 8irex abhotii, Pliyllohcenus dis- 
locatus, Spathius toraici, Spathius sp., Doryctes sp., and 
Rhyssa lineolata. 

Phorbia fusciceps Zett. 
(Det. by C. T. Greene) 

This small anthomyid fly is well knowm from the habit 
the larvae have of attacking the roots of radishes, cabbages, 
beans, etc. It has also been said to destroy the eggs of 
locusts and has been suspected of being parasitic upon the 
beet web-worm. Howard (1894, p. 272), however, believes 
this latter relation is very doubtful. 

Our specimens of this species were bred June 28 and 
July 6 from an exposed dead root of a living tree. The bark 
of this root was still adherent and was infested with Dryo- 
coetes ainericanus. The wood was beginning to decay and 
part of it was riddled by the mines of the larvae of Leptura 
vittata. Dryophthorus ainericanus and the larva of an 
unidentified elaterid were present. It is likely that this fly 



108 College of Forestry 

was breeding in the decaying bark and probably feeding 
upon the decaying inner bark or the fungi developing therein. 

Pollenia rudis Fabr. 

(Det. by C. T. Greene) 

There can be little doubt that our specimens of this fly 
bred upon decaying matter in the bark. They emerged under 
outdoor conditions in the middle and latter part of Septem- 
ber, 1916. The insects bred from the same lot of material 
are Polygraphus rufipennis, Dendroctonus simplex, Dryoph- 
thorus americanus, Asemum moestum, and Melanophila ful- 
voguttata. It is likely that the fly in question breeds in the 
decaying frass in the burrows of most any bark or wood- 
boring insect, and therefore we would expect in a larger 
number of breeding cages to obtain it from material derived 
from all regions of the tree and find it associated in this 
material with practically all of the borers. 

Epicallina argenticinctella Clem. 

(Det. by Carl Heinrich) 

This small moth belonging to the family Oecophoridce was 
taken from a cage containing part of the limbs of Tree I. 
But one specimen was obtained and it appeared in the cage 
July 7, 1916, It is not known whether the larva had lived 
in the wood or whether it had gone there to hibernate. How- 
ever, the latter is rendered unlikely by the fact that the limbs 
confined in this breeding cage were obtained from a standing 
tree at a distance of from 18 to 45 feet from the ground. 
This, together with the fact that members of this family are 
known to breed in " decayed wood and other dead material " 
(Smith, 1909, p. 560), makes the presumption that this 
moth had spent its larval life in the limbs more likely. The 
date of emergence (July 6) still further strengthens this 
view. 



Insects Bred from American Larch 109 

In conclusion the authors wish to express their gratitude 
to several sources for assistance received. Our thanks are 
due to Dr. E. P. Felt, State Entomologist of JSTew York, 
and his two assistants, Mr. Young and Miss Hartman, for 
their courtesies in placing the identified specimens in the 
State Museum at our disposal for comparison. We wish 
also to thank Dr. A. D. Hopkins for his kindness in placing 
his corps of specialists at our disposal in identifying speci- 
mens of Hymenoptera, Diptera and Lepidoptera. We wish 
also to thank these gentlemen directly: Mr. S. A. Rohwer 
for identifying the Hymenoptera, Mr. C. T. Greene for 
identifying the three Diptera, and Mr. Carl Heinrich for 
naming the moth. Such help is indispensible in problems 
such as this and we are indeed grateful for it. 



110 College of Forestry 

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On New and Known Coleoptera of the Families Coccinellidae and 
Cleridae. 
Jour. N. Y. Ent. Soc, Vol. 16, pp. 125-135. 

SCHWABZ, E. A., 1890. 

Notes on the Food Habits of Some North American Scolytidae and 
Their Coleopterous Enemies. 
Proc. Ent. Soc. Wash., Vol. 1, pp. 163-165. 

Sherman, John D., 1910. 

A List of Labrador Coleoptera. 

Journ. N. Y. Ent. Soc, Vol. 18, pp. 179-197. 

Slosson, Annie Trumsull, 1893. 

Spring Collecting in Northern Florida. 

Journ. N. Y. Ent. Soc, Vol. 1, pp. 148-152. 

Smith, John B., 1909. 

Catalogue of the Insects of New Jersey. 
34 figs., pp. 1-887. 

SwAiNE, J. M., 1909. 

Catalogue of the Described Scolytidae of America North of Mexico. 
N. Y. State Mus. Bull. 134, pp. 75-159, 17 plates. 

SWAINE, J. M., 1910. 

A New fepecies of Eccoptogaster. 
Can. Ent., Vol. 42, pp. 33-35. 

SWAINE, J. M., 1910 a. 

Some Insects of the Larch. 

Ent. Soc. Ontario, Kept. 41, pp. 81-88, 5 pi., 4 figs. 

Stebbing, E. p., 1914. 

Indian Forest Insects of Economic Importance — Coleoptera. 
London, 1914. 

Viereck, H. L., 1916. 

The Hymenoptera, or Wasp-like Insects of Connecticut (by H. L. 
Viereck with the collaboration of A. D. MacGilliway, C. T. 
Brues, W. M. Wheeler and S. A. Rohwer). 
Conn. Geol. and Nat. Hist. Survey, Bull. 22, 824 pp. 



Insects Bred from American Larch 115 

WiCKHAM, H. F., 1895. 

The Cleridae of Ontario and Quebec. 

Can. Ent., Vol. 27, No. 9, pp. 247-253. 

WiCKHAM, H. F., 1897. 

The Cerambycidae of Ontario and Quebec. 

Canad. Ent., Vol. 29, pp. 81-88, 105-111, 148-153, 169-173, 
187-193, 201-208. 

WOLCOTT, A. B., 1909. 

The Cleridae of the Public Museum of the City of Milwaukee. 
Bull. Wis. Nat. Hist. Soc, Vol. 7, pp. 93-102. 



il. ON THE INSECT VISITORS TO THE BLOS- 
SOMS OF WILD BLACKBERRY AND WILD 
SPIR^A — A STUDY IN SEASONAL DIS- 
TRIBUTION. 

By 

M. W. Blackman, Ph. D. 

[117] 



ON THE INSECT VISITORS TO THE BLOSSOMS 
OF WILD BLACKBERRY AND WILD SPIR^A — 
A STUDY IN SEASONAL DISTRIBUTION. 

By M. W. Blackman, Ph. D. 

No one who has collected insects during July and August 
in localities where the wild spiraea or meadow sweet {Spirwa 
latifolia Boikh.) is abundant can have failed to have 
observed what an excellent bait or trap the flowers of this 
plant furnish for the collector. This attractive quality has 
been taken advantage of for several years by the author both 
in the Catskills and the Western Adirondacks. In both of 
these regions insects are attracted to the flowers in great 
numbers, but this is much more noticeable in the former 
locality than in the latter. One of the striking characteris- 
tics of the insect fauna of the Catskills is the great relative 
abundance of the several genera of long-horned beetles com- 
monly known as the lepturids (Lej)turini) . These are 
attracted to the blossoms of wild spiraea in surprising num- 
bers — not only as regards individuals but also as regards 
species — and can readily be captured while feeding there. 

These beetles and also other insects have been collected by 
the author from spiraja in the Catskills at various times dur- 
ing the summer of 1913, 1914, 1915 and 1917. During the 
first two seasons the specimens taken from wild spiraea were 
not always kept separate fi-om those taken under other cir- 
cumstances, but definite data was preserved for all specimens 
taken in 1915 and 1917. In the former year (1915) the 
collections from spiraea were made on only two dates at an 
interval of two weeks (August 1 and August 15). When 
these two collections were pinned and placed side by side, 
the difference in the relative abundance of several species in 
the two lots was so striking as to suggest the desirability of 
a more detailed and systematic study of the insects visiting 
the blossoms of spiraea and other plants, with a view to 

[119] 



120 College of Forestry 

obtaining data on the seasonal distribution and seasonal suc- 
cession of certain insect forms. Such data was obtained 
during the past summer (1917) and is here presented. 

These observations were made at the Catskill Forest 
Experiment Station of the New York State College of For- 
estry, near Tannersville, IST. Y. The region covered is that 
extending north from the experiment station for about three- 
quarters of a mile and lying along each side of the road 
known locally as the County road. This varies in elevation 
from 2,150 feet at the experiment station to about 1,950 
feet where the County road joins the main road to Elka 
Park. The area covered consists of about half wooded land 
and half clearing, and is bordered both on the east and on 
the west by more extensive forests which have not been lum- 
bered for many years. The cleared land consists of irregular 
areas on each side of the road from which each year a sparse 
crop of hay is harvested. This yearly mowing keeps down 
young trees and also suppresses shrubs such as wild spiraea, 
blackberry and raspberry. Thus these shrubs are to be found 
only along the margins of the clearing, surrounding occa- 
sional isolated trees and large rocks, and in several swampy 
areas. The impression should not prevail, however, that the 
wild spiraea is either scanty or scattered, for such is far from 
being true. The area covered includes many thousands of 
the shrubs. Often a small clearing is bordered by a con- 
tinuous fringe of wild spiraea, and in one case a solid block 
of this shrub covering about a half acre occurs in one semi- 
swampy area. 

It will thus be seen that conditions here are ideal for many 
insects, especially such as feed upon pollen in their adult 
stage and live in dead or decaying wood in their larval con- 
dition. The adjacent forests, especially that towards the 
east, has been practically unmolested for years, and the 
numerous dead and decaying trees, which are always present 
in considerable numbers in undisturbed timber lands, serve 
as an excellent breeding place for the larvae of the very forms 
which as adults are characteristically feeders upon pollen. 
Thus it happens that these insects, notably the lepturids — 



Insects Visiting Blossoms of Spircea 121 

existing under conditions whicli are favorable both to the 
larval and to the adult stages — are strikingly more numer- 
ous than in any other region of the State with which the 
author is acquainted. 

In obtaining the data for this study the insects were col- 
lected from the flowers of approximately the same area at 
intervals of a week. Where the weather made it impossible 
to make the rounds at the stated day, the data was obtained 
the following day or the nearest favorable day succeeding. 
Thus a record was obtained of each seven-day period during 
the season. Most of the collections were made during the 
warmest part of the day between 1 :30 and 3 :30 p. m., when 
the insects supposedly were feeding in their maximum num- 
bers, and all were made on bright, sunshiny days favorable 
to the insects. It was impracticable to take every insect seen 
on the blossoms on the day of collection, as some of them 
inevitably escaped, but it is believed that approximately the 
same proportion of those active at each period were taken. 
'No insects were collected from spiraea or blackberry at times 
other than the stated interval except in a few cases where it 
was desired to record certain special data. The collections 
were made at intervals of a week, because there is good 
reason to believe that the life span of at least most of the 
insects which actually feed upon the honey or the pollen of 
flowers (which would include all but the casual visitors to 
spirsea blossoms) normally extends over more than that length 
of time. 

Before tabulating and discussing the results of this study it 
might be well to say a few words regarding certain controlling 
natural factors such as climatic conditions. Both the sum- 
mers of 1915 and 1917 were unusual in the lateness of the 
season — the former being remarkable for the cool weather 
as well as for the excessive rainfall during July and August 
in particular. Thus while in 1913 the wild spiraea was in 
full bloom and nearly at its maximum during the first week 
in July, and in the following year was at its best during the 
second and third weeks in July, in 1915 and 1917 the first 
blooms did not appear in the region studied until the middle 



122 College of Forestry 

of July (first blossom in 1917 seen on July 13), and the 
maximum was not reached until the first week in August. 

A comparison of the data collected during these four years 
makes unescapahle the conclusion that one can foretell the 
relative abundance of any one of a number of species, not in 
terms of the calandar date, but of the condition of the blos- 
soms which furnish them food. Thus the blossoms of wild 
spiraea (and doubtless other blossoms sought by insects) act 
as an indicator by which we may determine the seasonal 
distribution of certain insects depending upon them for food. 
In a sense the condition of the blossoms and the relative 
number of certain insect visitors are co-ordinated. Perhaps 
a more exact statement of the real relations might be made 
as follows : The relative abundance of the insect in the case 
of many lepturids and of some others, is really determined 
by the relative advancement of the season, and this is indi- 
cated by the condition of the blossoms upon which the insects 
depend for their adult food. In other words, while this 
synchronism works to the advantage of the insect and doubt- 
less also to that of the plant, we cannot assume that the rela- 
tion of cause and effect exists, but must rather look upon 
the two as separate phenomena both of which are dependent 
upon the same cause, the advancement of the season. Evi- 
dence leading to this conclusion will be found later, in the 
notes on a number of species. 

In the following tabulations all of the insects mentioned 
were taken from wild spiraea blossoms except those of the 
first two weeks and a few in the third week of July, 1917, 
which are from the blossoms of wild blackberry. As soon as 
the spiraea blossoms appeared in any numbers, the pollen- 
eating insects seemed to desert the berry blossoms and to feed 
nearly exclusively upon those of the spiraea. Thus the berry 
blossoms, although not the favored food supply of a number 
of these insects, seem to serve to tide the insects over till a 
better source is available. It is worthy of note in this con- 
nection that several of the lepturids had passed their maxi- 
mum before the appearance of the richer supply of pollen, 
but the greater number of individuals, even of these species, 



Insects Visiting Blossoms of Spirwa 123 

on the appearance of the spiraea blossoms, showed a decided 
preference for these. 

The blossoms of mountain azalea (Rhododendron canes- 
cens [Michx.] G. Don), which were in full bloom during 
the latter weeks of June, 1917, attracted quite a number of 
insects, but these were entirely or nearly entirely honey- 
feeding forms such as certain bees, moths and butterflies. 
Pollen-eating forms did not seem to be attracted to them. 

Other flowers which coincide more or less with spiraea in 
their period of inflorescence include especially the " pearly 
everlasting" (Anaphalis margaritacea [L.] B. &; H.) and 
several species of golden rod, notably the early golden rod 
(Solidago juncea Ait.), the wrinkled-leafed golden rod 
(Solidago rugosa Mill.), the white golden rod or silver 
rod (Solidago hicolor L.) and the flat-topped golden rod 
(Solidago graminifolia [L.] Salisb.). The flowers of all of 
these seem to exert an equal attraction to the honey-loving 
insects as do those of spiraea, but this is not true as regards 
the pollen-eating insects, although some of them, such as 
Chaulignathus pennsylv aniens, for instance, which occur in 
late August, must, on account of the rapid decline of the 
spiraea, depend upon the golden rod for most of their food. 
The species of golden rod most popular not only with this 
lamperid, but also with bees, yellow- jackets and hornets, is 
the flat-topped species, Solidago graminifolia. These began 
to appear in considerable numbers during the latter part of 
August (about August 24 in 1917) at a time when the 
spiraea was beginning its rapid decline. 

In the following pages will be found some additional data 
and certain conclusions regarding a number of the species 
mentioned in the above table. Also notes on a few species not 
taken in 1917 but found on spiraea during some previous 
summer are added. It will be readily seen, both from the 
table and from these notes, that most of the abundant and 
interesting beetles on spiraea belong either to the subdivision 
of Ceramhycidw known as the Lepturini or to the family 
Mordellidw. Both of these groups are well known flower 
frequenters and there can be no doubt that they depend upon 



124 



College of Forestry 



the pollen of flowers for their food. The richness of spiraea 
blossoms in this material is doubtless the reason for its popu- 
larity with these insects. 

NuMBEE OF Specimens of Coleopteka Taken Each 
Week, July 1-September 1, 1917. 



Species 


'a 


1-5 


1 
1-5 


00 

1-5 


1-5 


^1 

< 


00 


. 1 






8 
11 
2 
1 
1 


3 

8 


1 
5 














Leptura pubera Say 

Leptura sphaericollis Say 


7 








































1 

4 


4 
6 

\ 
1 
1 


1 
13 














4 


S 


3 




















9 
.. . 

7 
1 

2 


16 
1 

is' 


15 
. .. . . 

1 


15 
2 


3 

1 










1 
















4 


1 


1 




















14 
1 


17 
5 
1 


12 
3 
17 


5 
4 
9 


3 










1 










3 


Oberia iripunctaia Swed 


1 


1 
2 




























1 
1 
1 


1 


4 




2 






















1 
1 








































2 

1 







































1 
2 










1 








2 
1 
1 








1 






























1 
















1 


















1 


























1 








Chaulignathtis pennsylvanicus DeC 












. .i 


4 
1 
1 

1 


7 
























2 
4 
















9 


5 
1 


1 




2 












1 


















1 
2 

1 










1 

16 










11 


9 


+ 


+ 


+ 














2 


3 


2 


1 


1 
2 
2 






















3 


2 


1 


3 


1 


1 








1 


Odontocoryniis scuielluni-albxun Say 






1 


3 


2 




4 


2 





Leptura mutahilis Newn. As will be seen from the table, 
this species was at its maximum in 1917 during the first half 
of July. All but two specimens were taken from wild black- 



Insects Visiting Blossoms of Spircea 125 

berry blossoms. Of these two, one was from a spirsea 
blossom, while the other was taken June 22 from the surface 
of a beech log felled three years before. Of the twelve speci- 
mens taken in 1917, eleven of which were from flowers, eight 
are of the testaceous variety known as variety luridipennis. 
L. mutabilis has been bred from a small branch of a dying 
alder obtained near Syracuse, and Mr. Carl Wright, a stu- 
dent in the college, has taken a specimen of the testaceous 
form from the wood of hemlock at Cranberry Lake, N. Y. 
Apparently it has a variety of hosts, 

Leptura puhera Say. The seasonal distribution of this 
species nearly coincides with that of L. mutabilis, but extends 
slightly later. Specimens were numerous upon blackberry 
blossoms until the appearance of the spiraea blooms, when 
they showed a very marked preference for the latter. Dur- 
ing the first three weeks in July this species was decidedly 
the most common lepturid. In 1914 several specimens were 
taken from daisy heads. 

Leptura sphwricollis Say. But three specimens of this 
species were taken in 1917, two from wild blackberry in the 
first week in July and one from mountain azalea on June 20, 
These all are of the typical form with the black prothorax. 
Three specimens were also taken in July, 1914, of which two 
are of the typical coloration and one has the red prothorax 
characteristic of the variety ruficollis. 

Pachyta monticola Rand. But one specimen of this lepturid 
was taken during the last season and it was obtained from 
a blackberry blossom on July 3. The only other specimen 
taken by the author from this same general region was from 
the bark of recently felled balsam tree, July 8, 1914. ]^o 
breeding data is available, but it is believed the specimen 
captured on balsam was preparing to oviposit. Wickham 
(1897, p. 171) records the adult from the blossoms of wild 
rose. 

Leptura lineola Say. This species, which in the region 
studied is never one of the most abundant lepturids, has a 
seasonal distribution extending over July, the maximum 



126 College of Forestry 

number in 19 lY having been taken during the third week. 
One specimen was also taken in July, 1914, and two on 
August 1, 1915. It has reached its maximum numbers about 
the time the wild spiraea begins to bloom. 

Leptura vittatcv Oliv. This very abundant species begins 
to appear in some numbers before the wild spiraea blossoms, 
but does not reach its maximum until these flowers are nearly 
at their best. In both 1915 and 1917 they had practically 
disappeared by the middle of August. Copulating pairs 
were seen July 17 and 27 (numerous) and August 17. The 
specimens show a considerable range of variation in the 
coloration of the elytra but this variation is within much 
narrower limits than in L. miitahilis L. vagans, etc. L. vit- 
tata has been bred from dead larch wood but doubtless breeds 
in spruce and balsam in the Elka Park region as little or 
no larch is present there. 

Leptura nana IsTewn. Only two specimens of this small 
species have been taken from Elka Park. Of these, the one 
taken July 20, 1917, is entirely black, while the other speci- 
men taken July 23, 1914, is of the variety hcematites charac- 
terized by the red prothorax. Nothing is known regarding 
its breeding habits. 

Leptura proxima Say is perhaps the most abundant 
lepturid in the Elka Park region, its only rival in this respect 
being Typocerus velutinus. In all, some 60 specimens were 
taken in 1917, all but one of which were on the blossoms of 
spiraBa. This single exception was on elderberry blossoms 
{Samhucus canadensis L.), but apparently had merely 
alighted there as it was not feeding. The seasonal occur- 
rence of this species may be said to correspond nearly exactly 
with that of the wild spiraea blossoms. It begins to appear 
with the first blossoms of the spiraea, is at its maximum 
during the greatest abundance of these, and decreases in 
numbers with the waning of the flowers. The data from 
other years agrees entirely in this respect. Copulating pairs 
were common throughout the last week in July and the first 
three weeks in August. Wickham (1897, p. 192) reports 



Insects Visiting Blossoms of Spiraea 127 

this species as having been bred from maple. No additional 
data is at hand. 

Leptura vagans Oliv., while never as numerous as several 
other species, has about the same seasonal distribution as 
L. proxina. Six specimens were taken in 1917 — three of 
the typical variety having black elytra with a reddish brown 
marginal stripe and three having the elytra entirely testa- 
ceous. In 1915 eight specimens showing about the same 
seasonal distribution were taken ■ — two on August 1 and six 
on August 15. Of these, three are of the testaceous variety 
and five are typical. The larvae have been reported (Wick- 
ham, 1897, p. 192) as boring in yellow birch and hickory 
and it is likely that the former of these two trees acts as host 
in the Elka Park region. 

Strangalia luteicornis Fabr. Only three of these were 
taken in the region studied — not a sufficient number for me 
to venture any statement regarding the period of greatest 
abundance. J^othing is known regarding its larva] host. 

Leptura ruhrica ^rj begins to appear in numbers during 
the second week of the blooming season of spiraea and con- 
tinues in considerable numbers for nearly a month. In 1914 
thirteen specimens were taken on July 23 and this species 
was doubtless at its maximum at that time, this being entirely 
in accord with the data on other forms which show that the 
season of 1914 was about two weeks earlier in its advance- 
ment than in 1915 and 1917. My field notes record copulat- 
ing couples as common on July 27 and August 3. L. riibrica 
has been bred from hickory at Syracuse. 

Leptura pleheja Eand. Only one specimen has been taken 
by me in the Elka Park region and this gives no basis for 
a conclusion regarding seasonal distribution. However, from 
the fact that I have specimens from Cranberry Lake taken 
on July 12 and September 16 it is believed this species may 
occur at any time in late summer. It is apparently not very 
common in either of the regions mentioned. An adult of 
this species has been obtained from spruce wood in the Cran- 
berry Lake region of the Adirondacks. 



128 College of Forestry 

Typocerus velutinus Oliv. is one of the extremely common 
and numerous forms upon spiraea blossoms. It begins to 
appear soon after these flowers and occurs in maximum num- 
bers when they are at their best. In general its seasonal 
distribution is similar to that of L. proxima, but appears to 
be about one week later both in its beginning and its decline. 
The data for the various years check very closely when 
judged in terms of the advancement of the season or of the 
condition of the blossoms upon which the adults depend for 
food. Copulating pairs were observed on July 2Y, August 3 
(common) 9 and 17 respectively. T. velutinus shows a very 
considerable degree of variation in its color pattern. The 
light bands are nearly obsolete in some cases while in others 
they are so enlarged as to show a tendency to fuse more or 
less. Several adults have been bred from much decayed 
hickory at Syracuse and it is likely that it breeds in decayed 
wood of a variety of species of trees. 

Leptura cordifera Oliv. has the same seasonal distribution 
as T. velutinus but in the region studied is not so extremely 
common as this other lepturid. There is much variation 
here as regards relative amount of black and yellow on the 
elytra. It has been bred from chestnut (Lugger, 1884, 
p. 204). 

Leptura canadensis Oliv. The seasonal distribution of 
this form is interesting from the fact that it appears later 
in the summer than any of the other lepturids taken on wild 
spiraea. Another interesting fact is that up until August 13, 
but a single specimen had been seen and yet in this week 
seventeen specimens were taken — it being the most numer- 
ous lepturid at that time and remaining so for the rest of 
the season. Of the 30 specimens taken in 1917, six are of 
the variety erythroptera and the rest, which are of the more 
typical coloration show considerable variation in the amount 
of red upon the elytra. There is considerable disproportion 
in the number of males and females taken from the flowers, 
for of the thirty specimens twenty-four are males. Of the 
red-winged variety three were males and three females. 



Insects Visiting Blossoms of Spiraea 129 

One sexual difference in this species is that in the male 
the antennae are strongly serrate and are entirely or nearly 
entirely black while in the female they are quite feebly 
serrate and according to Leng (1890, p. 189) joints 4—11 
are annulate with yellow. As a matter of fact, the antennae 
in both sexes are subject to considerable variation as regards 
color. The following data on the variation in the antennae 
of the males of Leptura canadensis is based on a study of 
fifty-two antennae from thirty-one individuals, some of the 
specimens having lost on antennae : 

Antennae entirely black 33 from 19 individuals. 

Antennse with joint 8 with more or less yellow 

at base 18 from 11 individuals. 

Antennae with joint 6 with more or less yellow 

at base 1 from 1 individual. 

Antennae with joints 6 and 8 more or less yel- 
low at base 1 from 1 individual. 

Except in one case, the two antennae on the same indi- 
vidual were similar. 

The variation in the female antennae is more striking. 
The thirteen females studied agree in having joints 1, 2 and 
3 and 11 entirely black and joints 5, 6 and 8 with more or 
less yellow. The following tabulated data on variation in the 
antennae of the female of Leptura canadensis is based on a 
study of twenty-two antennae from thirteen individuals. 

With joints 4-10 all more or less yellow... 7 from 4 individuals. 

With joint 4 entirely black 3 from 2 individuals. 

With joint 7 entirely black 11 from 7 individuals. 

With joint 9 entirely black 14 from 8 individuals. 

With joint 10 entirely black 4 from 3 individuals. 

With joints 7, 9 and 10 entirely black 3 from 2 individuals. 

With joints 7 and 9 entirely black 10 from 6 individuals. 

With joints 8 entirely or nearly entirely yel- 
low 19 from 11 individuals. 

With joints 6 entirely or nearly entirely yel- 
low 14 from 9 individuals. 

With joints 6 and 8 entirely or nearly en- 
tirely yellow 13 from 9 individuals. 

It will be seen from the above that in the specimens from 
the Elka Park region taken in 1915 and 1917 there is a ten- 
dency toward joints 4, 7, 9 and 10 to be entirely black, and 
6 



130 College of Forestry 

this is especially noticeable in joints 7 and 9. There is a 
still more decided tendency for joints 6 and 8 to become 
entirely yellow, this condition being especially true as 
regards joint 8. 

Dr. Felt (1906, p. 670) reports this lepturid as breeding 
in spruce and hemlock and the author has taken it from 
spruce. 

Other Lepturids. In addition to the Lepturids listed 
above, all of which were collected in 1917, there are a number 
of other species taken other years which should be men- 
tioned. 

Acmeops directa Newn. Four specimens of this lepturid 
were taken from the flowers of wild spiraea and other blos- 
soms during the third week in July, 1914. Considerable 
variation in color is noticeable in these sj)ecimens. 

Bellamira scalaris Say. But one specimen of this striking 
insect has been taken by me in the vicinity of Elka Park 
and this was obtained from spiraea bloom during the third 
week in July, 1914. This insect habitually breeds in yellow 
birch (Packard, 1890, p. 486). Large numbers of the larvae, 
pupa3 and newly transformed adults were found in a birch log 
in the region of Cranberry Lake, N. Y., in July, 1917, by 
Prof. C. J. Drake of this Department. 

Leptura suhhamata Rand. Two males of this species were 
collected July 23, 1914, from wild spiraea near Elka Park, 
Wickham (1897, p. 192) reports it as having been taken 
in a beech log. 

Leptura suhargentata Kirby. Seven specimens of this 
species were taken in July, 1914, four from flowers (prob- 
ably spiraea, but notes do not specify) and three taken on the 
wing and upon felled balsam near the top of Twin Mountain. 

Leptura circumdata Oliv. Four specimens of this species 
were obtained from spiraea blossoms July 23, 1914. Prof. 
C. J. Drake reports having cut an adult of this species from 
a spruce log near Cranberry Lake in July, 1917. 



Insects Visiting Blossoms of Spircea 131 

Leptura hiforis Newn. One specimen of this beetle was 
taken July 23, 1914, from spiraea bloom, ISTothing is known 
regarding its breeding habits. 

Leptura vihex Xewn. A single example of this species was 
taken July 10, 1914, from leaves about half way up Spruce 
Top Mountain, It is not known that this species ever visits 
wild spiraea but from the great uniformity in habits shown 
by the adults of this genus it seems probable, 

Leptura aurata Horn, Two specimens were taken from 
spiraea July 23, 1914. Nothing further is known regarding 
its habits. 

Only a few species of Coleoptera other than the lepturids 
already treated were taken in sufficient numbers for any 
conclusions to be drawn regarding their seasonal distribution, 
A few of these are briefly mentioned below. 

Oherea tripunctata Swed. and Oherea bimaculata Oliv. 
may be mentioned together. Two specimens of each were 
taken during the first two weeks of July, 1917, from blossoms 
of wild blackberry in the stems of which they are said to 
breed. 

Clytanthus ruricola Oliv. This cerambycid occurs at its 
maximum numbers in late July and early August at the 
heighth of the wild sj)ir8ea season. While it frequents these 
flowers by preference it is also occasionally seen on the 
flowers of the daisy, golden-rod and others. A number of 
specimens of this form have been bred from hickory at Syra- 
cuse but no hickory occurs in the Elka Park region and it 
must depend upon some other wood. In one case a specimen 
was observed which was apparently preparing to oviposit in 
beach and it is probable this serves as a larval host. 

Chaulignafhus pennsylv aniens DeG. is well known to be 
a late season form. It appears about the middle of August 
and does not occur in great numbers until the spiraea blos- 
soms are decidedly on the wane and the golden rods are at 
their maximum. For that reason much larger numbers are 
to be seen on golden rod than upon spiraea, Yet in spite of 
this it will be seen from the table that the specimens actually 



132 College of Forestry 

taken from spiraea were continually on the increase up to 
September 1, although the numbers of these blossoms were 
rapidly decreasing. 

Trichius affinus Gory. Although this beetle occurs in 
some numbers throughout the entire summer, it is more 
numerous in July. It is found in the early season most fre- 
quently on the blossoms of raspberry, blackberry ami dai.-y 
but with the appearance of the spiraea bloom it shows a 
decided preference for this. 

Five species of Mordellidce were taken from the blossoms 
studied and three were very common. The most common 
form is Anaspis rufa Say, which is present in considerable 
numbers from the third week in July until the close of the 
season. No effort was made to collect these consistently after 
the third week in July and on several of the weeks the speci- 
mens were so numerous that they were not saved. The 
general assertion, however, may be safely made that the 
seasonal distribution is timed to that of the spiraea bloom- 
ing period. Mordellistena hiplagiata Helm, seems to reach 
its ma:ximum before the spiraea bloom is at its best and no 
specimens were taken after August 17. Mordella marginata 
Melsh. has about the same seasonal distribution as Anaspis 
rufa. 

Odontocorynus scutellum-alhum Say. This small curcu- 
lionid was taken on no other flower than that of wild spiraea 
where it appeared to be feeding upon pollen. Its occurrence 
coincides very closely with that of this blossom. A pair in 
copulation was observed July 25, 1917. 

It is probable that most of the remaining beetles which are 
included in the table, but are not mentioned in the notes, 
are more or less casual or accidental visitors and are not on 
the flowers in search of food. Probable exceptions to this 
statement are furnished by Anthrenus castanece Melsh. and 
Epicauta pennsylvanica DeG., both of which are probably 
pollen eaters. 



Insects Visiting Blossoms of Spircea 



133 



XuMBER OF Specimens of Hymenopteea Taken Each 
Week, July 1-September 1, 1917. 



Species 


"-5 




<-> 


00 

3 
>-5 


1 -^ 

IM M 

•-5 


< 


00 


10 

. 1 
< 


1 '-' 
. 

< 


Allantus duhius Norton | 






7 S 
11? 


2S 
79 


5^ 
1? 














2? 

2<5 
2? 


39 

i<; 

69 






f 


















1? 
1 


39 


39 






















5 
4 








1 






























1 


1 


1 

1 
1 
2 




Amblyleles unifascialorius Say. . . , 
































Psammochares lucttiosus Cresson. . 










1 


3 




2 


Psammocharea ethiopa Cresson. . . . 










1 


















1 




Odynerus catshilli De Saussure. . 




1 








2 


1 
1 




























1 
1 

2 




Odynerus collega De Saussure 


















Odynerus albomarginatus De Saus- 




















2 
















Vespula (,Vespa) diabolica De 


1 




1 


1 


3 
1 


10 

+ 

6 
1 
2 


+ 
+ 
+ 


+ 


Vespula (Vespa) maculata Linneus 




+ 














+ 






























4 


















1 
1 
















1 


1 


1 




1 

1 












Halictus provancheri Dalla Torre. . 


2 




3 




5 


1 






1 

1 
2 






2 


..... 


4 
2 
3 








1 






2 
1 




3 


2 










1 
















1 






















1 
1 


1 

1 


"2" 
1 

+ 

+ 


1 
5 

1 


+ 
+ 
+ 


+ 










+ 










+ 


Formica fusca fusca Linn 
var. subaenescens Emery 


+ 
























+ 


Formica neogagates neogagates 














+ 


+ 


Camponotus herculaneus Linn 
















+ 


Camponotus fallax Nyl 


















+ 























134 College of Forestry 

The preceding table of hymenopterous visitors to the 
blossoms of wild spiraea perhaps needs little explanation or 
comment. It should, however, be remembered that these 
insects represent forms having rather diverse habits and 
modes of life. Thus the objects gained by the insects in 
visiting the flowers varies considerably. Some of them 
doubtless obtain only honey ; others — a more numerous class, 
including the various bees and social wasps — seek both 
honey and pollen; others, perhaps, are in search of pollen 
only; while still others are in search of their prey. A few 
should be classed as casual visitors only — having alighted 
upon the blossoms by accident. 

The number of specimens of most of the species listed in 
the table is not sufficiently great to warrant any deductions 
regarding seasonal distribution. Some few species, however, 
occurred in sufficient numbers to make a tentative conclusion 
desirable. Some of these are briefly discussed below. 

Allantus dubius Nort. This saw-fly begins to frequent 
the flowers of spiraea in considerable numbers during the 
first week of the blossoming season. Indeed they seem to be 
at their maximum at this time and in succeeding weeks are 
gradually on the decrease. It is not known upon what this 
insect fed before the appearance of the spiraea, as there were 
none taken from wild blackberry or other blossoms. I^othing 
was found regarding the breeding habits. 

Allantus hasilaris Say begins to appear upon the spiraea 
during the fourth week of July, reaches its maximum at the 
middle of August and no specimens were taken after August 
25. This species is not quite so numerous as the sister spe- 
cies, only eighteen specimens being taken, and of these only 
three are males. 

Vespula {Vespa) diaholica De Saussure, one of the com- 
monest of the colonial wasps, may be taken as a good example 
of insects of this genus and general mode of life. This insect 
is a frequent visitor to wild spiraea in search both of honey 
and pollen. It, however, does not visit the blossoms of this 
plant to the exclusion of other flowers, but during the height 
of the blooming season seems to prefer these flowers to all 



Insects Visiting Blossoms of Spircea 135 

others. Later when 8olidar/o graminifolia is in full bloom 
and is very abundant these blossoms are sought bv the yellow 
jackets in great numbers. Even at this time, however, a 
proportional number apparently visit the few spirsea blossoms 
remaining. Regarding the seasonal distribution of the yellow 
jacket and of other species of the same genus, as would be 
expected of a colonial form, there is a rather gradual numeri- 
cal increase during early and midsummer and a very rapid 
increase later in the season. This rapid increase in 1917 
commenced during the first week in August and by the 
middle of this month this species was so common that speci- 
mens were no longer retained. However, it was apparent 
that they were rapidly increasing in numbers up to the time 
observation ceased, September 2, at which time individuals 
of the various species of Vespula far outnumbered all other 
flower visitors combined. 

Bremus (Bomhus) terricola Kirby. This bumble-bee, 
which apparently is the most common one frequenting spirsea 
blossoms in the Elka Park region, may be used as an example 
of the genus. Its seasonal distribution as shown by its rela- 
tive abundance upon spirsea is similar to that of the yellow 
jacket although it is never quite so numerous. This is to be 
expected f]-om the similarity in habit between these forms 
both of which are colonial forms and visit the blossoms in 
search of honey and pollen. 

The data regarding most of the remaining Hymenoptera 
is not complete enough to warrant important conclusions. In 
the case of such forms as the various species of Psammo- 
cliares, Odynerus, Eumeries, Solenius and Cerceris, the visits 
of which to spirsea blossoms are probably as likely to be in 
search of prey as for obtaining honey or pollen, we would 
not expect much uniformity of occurrence. Therefore a 
curve showing the numbers occurring at stated periods on 
one particular species of flower would not be so likely to 
represent the true seasonal distribution of the species because 
prey could likely be obtained from many other sources. 

The ants listed above, the species of which were kindly 
determined by Mr. M. R. Smith of the Bureau of Ento- 



136 



College of Forestry 



mology represent only specimens collected accidentally except 
those taken in the last week in August. It might be said, 
however, that ants are constant visitors to the blossoms of 
spirsea and blackberry throughout the entire season. They 
are perhaps the most consistently numerous insect visitors as 
they are to be found working among the blossoms in almost 
eveiy kind of weather except during heavy rain storms and 
even then some are stranded there. It is likely that their 
primary object is to obtain nectar but it is by no means 
improbable that they eat pollen as well. 

Number of Specimens of PIemiptera Taken Each 
Week, July 1-September 1, 1917. 



Species 


3 


1-5 


_4 

a 

■-5 


00 
1-5 


1 ■* 

o . 

IM M 

1-5 


< 


00 
•< 


< 


< 




2 




























1* 

la- 

In- 








Euschistus variolarius P. B 










-1- 


In- 












Meadorus lateralis Say 














1 















-i- 






















2a-ln 


In 


Phlegyas abbreviatus Uhl 














1 
















In 


2a 




Neurocnlpus nubilus Say 










1 

2 












1 
1 


1 


2 


4 
1 


3 




1 




1 




Lygus pratensis Linn 




4 










2 




























3 
1 




Lopidia instabile 












2 


5 

4 

1 
1 


1 








2 


7 


1 


1 


Aphrophora quadrinolata Say 














1 





















* The letter "a" signifies adult, the letter "n" signifies nymph. 

Probably little comment is necessary regarding the 
Hemiptercb listed above. It is likely that most of these 
should be looked upon as casual visitors, and not as forms 
which visit the flowers to obtain some portion or product of 
these for use as food. Where such a casual or accidental 
relation exists, it is apparent that quantitative data of the 
insect on the flower would not be likely to furnish a reliable 
foundation upon which to base conclusions regarding its sea- 



Insects Visiting Blossoms of Spircea 



137 



sonal abundance. It is possible that a few of these bugs 
actually were obtaining food from the flowers, and if it 
should prove that the spiraea is the favorite source of food, 
the data for such forms should lend itself to the formation 
of a reliable curve showing seasonal distribution. In the 
case of Lopidia instabile, one of the most consistent hemip- 
terous visitors to spiraea blossoms, the curve is at least not 
unbelievable. 

I am indebted to Prof. C. J. Drake, my colleague, in the 
department for his kindness in identifying the Hemiptera, 
listed in the table. 



Number of Specimens of Diptera Taken Each 
Week, July 1-September 1, 1917. 



Species 


>-5 


-co 

1-5 


>-5 


00 






00 

1 

< 


< 


< 




1 


1 
1 






















































1 




















1 

1 








































8 


2 


























































Chrysogaster pulchella Will 


















Criorhina intersisteus Wk 






























2 
1 
2 
1 
1 


3 




Syritta pipiens L 














Eristalis tenax L 




















































Eristalis bastardi Macq 














1 


1 


















1 


Eurosta coma Wd 


















2 





















Of the Diptera listed in the accompanying table only a 
few should probably be classified as other than casual visitors 
to the blossoms of spiraea. It seems certain that some at least 
of the Syrphidw obtain nectar from these flowers, and if 
these insects were present in any considerable numbers, they 
should furnish reliable data regarding the season of greatest 
abundance. However, the numbers in all cases were so lim- 



138 College of Forestry 

ited as to make it unwise to deduce more than rather general 
conclusions. Thus we can say that Pangonia tranquilla is 
most ahundant in the Elka Park region when the blossoms 
of wild spiraea are at their maximum, which in 1917 was 
during the first half of August. Similarly we may say that 
Spilomyria fusca begins to appear at about the same time 
but does not reach its maximum numbers until the spiraea 
blossoms are decidedly on the wane. This species then, does 
not appear until Vespula marginata and other similar black 
and white hornets of which it is a mimic, are becoming quite 
numerous, and does not reach its maximum numbers until 
these hornets are the most abundant flower visitors. The very 
striking resemblance of the fly and hornet can but be 
admitted by anyone who has collected both from the same 
flowers. 

I am under obligations to Prof. A. S. Hine of Ohio State 
University for his kindness in identifying the flies in the 
above table. 

In addition to the various C oleoptera, Hymenoptera, 
Hemiptera and Diptera which are listed in the accompany- 
ing table a considerable number of insects belonging to other 
orders were observed on spiraea blooms. Doubtless the major- 
ity of these were casual visitors which would be no more 
likely to be found on blossoms than on any other structure 
occurring in the same location. This is certainly true of 
several species of dragon flies, grasshoppers, katydids, caddis- 
flies, etc. In addition to these, several moths and a number 
of butterflies were seen upon spiraBa blossoms, but no effort 
was made to obtain quantitative data of any of these. The 
following butterflies were observed upon the blossoms of 
spiraea: Papilio turnus Linn, P. polyxenes Fabr., Feniseca 
tarquinius Fabr., Basilarchia arfhemis Druiy, B. astyanax 
Fabr., B. archippis Cram., Grapta progne Cram., Argynnis 
cyhele Fabr., and Erynnis sp. The moths taken are fewer 
in number of species and include Hcemorrhagia diffinis 
Boisd., LycomorpJia pholus Drury, Ctenucha virginica 
Charp., Synanthedon hassiformis Walk., 8. acerni Clem., 
and Oxyptilis sp. These moths apparently were on the 



Insects Visiting Blossoms of Spircea 139 

flowers in search of food as some of them when taken were 
observed to have their probosces uncoiled and searching 
about among the flowers for the nectaries. 

In arriving at conclusions regarding seasonal distribution 
and seasonal succession of insects from data such as here 
presented, it is wise to scrutinize such data with the greatest 
of care. It has already been shown that the collections were 
made as nearly as possible at intervals of seven days. But 
it was considered to be more important that the climatic 
conditions — temperature, moisture, light and wind — 
should be as nearly uniform as possible, than that the interval 
should be exactly one week. Of course, some variation of 
these conditions were inevitable and unavoidable but the 
collection days were as uniform as possible and the results 
are believed to be entirely trustworthy in this respect. 

The validity of conclusions from such data is also depend- 
ent upon the uniformity with which each species of insect 
seeks the blossoms from which the collections are made. 
Thus in the case of some of the insects from spiraea blossoms, 
it is believed that the number taken on any date represents 
a fairly definite per cent of those actually in the adult con- 
dition at that time. In other cases it is believed that the 
numbers taken have not even an approximately definite rela- 
tion to the numbers actually out. The object of the insect's 
visit to the blossom has much to do with the reliability of 
the data for the purpose mentioned. Thus, if the insect is 
in search of honey or of pollen or of both of these, and if 
observations have shown that the blossoms in question are 
the favorite source of this material, the data should be reli- 
able. If the insect visitor is in search of insect prey, the 
data is not so valid unless it is established that the predaceous 
or parasitic form is in search of some particular species 
which is usually to be found only on the flower in question. 
If the insect is an accidental or casual visitor which has 
happened to alight upon the flower the data is valueless, as 
the number taken from flowers would bear no fiixed relation 
to the actual numbers at the time. 



140 College of Forestry 

It would seem then, that in the case of an insect feeding 
upon pollen or honey, or both, which has shown a preference 
for that derived from the spiraea blossom, a curve showing 
its numerical abundance upon this flower at fixed intervals, 
should represent its seasonal distribution. The accuracy of 
this curve would depend upon the factors already mentioned. 
The larger the number of insects taken at each period and 
the larger per cent collected of those actually out, the more 
reliable will be the curve. It is apparent that when the 
number of specimens of a consistent visitor to spiraea is great 
enough, quantitative data furnishes material for the con- 
struction of a reliable curve showing seasonal numerical 
distribution. 

A number of curves from such data are shown in the 
accompanying figure. It will be seen that typically they fall 
into two general classes dependent upon the habits and mode 
of life of the insect. In cases of species which live as indi- 
viduals (t. e., not in colonies), the curve typically shows an 
even rise, which may be either gradual — such as Allantus 
hasilaris — or sudden — such as Leptiira canadensis — until 
a maximum is reached. This maximum may be held for 
several weeks followed by regular decline, as in Leptura 
proxina, or a more or less gradual drop may follow the 
maximum immediately, as in the curves of Typocerus velu- 
tinus and Leptura canadensis. The irregularity in the curve 
of Leptura cordifera is due to the small number of specimens 
of this species taken as it is apparent that in a small number, 
a variation of one or two individuals causes a relatively great 
irregularity in the curve. 

The curve showing the seasonal distribution of colonial 
insects such as the yellow-jackets, hornets and bumble-bees, 
is of quite a different character as will be seen by studying 
G and H of the accompanying figure. Here the insects (fer- 
tile females) appear in small numbers with the beginning of 
the flowers in early summer. These little more than hold 
their own until the season has advanced to such a degree that 
the spiraea blossoms have about reached their maximum, when 
with the appearance of an ever-increasing number of workers, 



Insects Visiting Blossoins of Spiraea 



141 



Curves Showing the Seasonal Distribution of Certain 
Insects TyricAL of Those Visiting the Blossoms 
of Wild Spir/ea. 




Q er H A. D.B»F 



E.A. P. DjSC. 



A — Leptura proxima E — Allantus dubius 

B — Typocerus velutinus F — Allantus basilaris 

C — Leptura canadensis G — Vespula {Vespa) diabolica 

D — Leptura cordifera H — Bremus {Bombus) terricola 

S — Blossoms of Spircca latifoUa. 



142 College of Forestry 

the curve showing numerical abundance soars upward and 
continues rising until the onset of cold weather. It is not 
known exactly what would be the course of the curve fol- 
lowing the first heavy frost, but there would doubtless be a 
very rapid drop as the wasps and bees sought hibernation 
quarters. 

One interesting observation regarding the seasonal distri- 
bution of several of the lepturids especially, is apparent both 
in the table and in the curve. This is the fact that all of 
the late summer lepturids showed a rapid decrease in num- 
bers after August lY, 1917. At this date the spiraea blos- 
soms were only just beginning to wane and several of the 
lepturids as Leptura proxima and L. canadensis were still 
at their maximum and L. cordifera and Typocerus velutinus 
were but little below their highest numbers. Yet by the 
following week L. proxima had nearly disappeared and there 
was a very striking decrease in all of the lepturids. This 
rapid drop in numbers then occurred in 1917 before any 
frost and was out of all proportion to the decrease in spiraea 
blossoms. A careful search was made upon the blossoms of 
other plants, and while the various Vespidce and Bombidce 
and beetles such as Cliaulignathus pennsylv aniens were pres- 
ent there in ever-increasing numbers no specimen of lep- 
turids were found. It apparently is a case where insects cease 
feeding on the approach of cold weather but a considerable 
time before killing frosts occur. In the cases of insects 
which hibernate either as adults or as immature forms such 
cessation of feeding before the fall frosts might be spoken 
of as an adaptive response, as it seems to be generally under- 
stood that insects are better able to hibernate at low tem- 
perature when the digestive processes have ceased some time 
and the alimentary canal has been entirely emptied of food 
and waste materials. The species in question, however, 
doubtless never hil)ernates in the adult condition, and it is 
believed that the response to the cool nights which herald 
the approaching frosts results in cessation of feeding and 
more prompt ovipositing on the part of the adults already 
out. It is likely also that the cool nights react upon the 



Insects Visiting Blossoms of Spiraea 143 

larvae and pupse which are about ready to transform, in such 
a manner as to postpone the completion of their life cycle 
until the following summer. This latter is in line with 
numerous observations of the author which show that the 
duration of the life history of many species of boring insects 
is subject to considerable variation, due often to apparently 
only small differences in the environmental conditions. 

My thanks are due to several men for the assistance they 
have given by identifying specimens. I wish to thank Dr. 
Harry P. Brown of the Department of Dendrology of this 
college, for identifying the several plants mentioned; Prof. 
C. J. Drake, my colleague in the Department of Entomology 
of this college for naming the Hemiptera; Prof. J. S. Hine 
of the Department of Zoology and Entomology, Ohio State 
University, for naming the flies, and Mr. M. R. Smith of 
the Bureau of Entomology, U. S. Department of Agricul- 
ture, Baton Rouge, La., for identifying the ants. 



144 College of Forestry 

LITERATURE CITED 

Felt, E. P., 1905-1906. 

Insects Affecting Park and Woodland Trees, N. Y. State Mus. 
Memoir 8. 

Leng, Chas. W., 1890. 

Synopsis of Cerambycidae — Lepturini, Entomologica Americana, 
Vol. II, pp. 65-69, 97-98, 104-110, 156-160, 185-200, 213-215. 

Lugger, Otto, 18S4. 

Food Plants of Beetles Bred in Maryland, Psyche, Vol. 4, pp. 203, 
204. 

Packard, A. S., 1890. 

Insects Injurious to Forest and Shade Trees, Fifth Report, U. S. 
Ent. Comm's. 

Smith, J. B., 1909. 

The Insects of New Jersey, Annual Report of N. J. State Museum 
for 1909. 

WiCKHAM, H. F., 1897. 

The Cerambycida; of Ontario and Quebec, Canad. Ent., Vol. 29, 
pp. 169-173, 187-193. 



EXPLANATION OF PLATES. 

All photographs were made by the senior author. 



Plate 1. 

Fig. 1. View of the iniier bark of American larch, show- 
ing the burrows of Dendroctonus simplex. The wider 
passages are the egg-galleries made bj the adults, while the 
.shorter burrows at right angles to them are the larval mines. 
]^ote the arrangement of the larval mines in alternate groups 
of from three to six on opposite sides of the egg-gallery. This 
is best shown in connection with the egg-gallery at the right- 
Jiand side of the picture. About four-fifths natural size. 



Plate I. 




Plate II. 

Fig. 2. Top of x\merican larch with the outer bark 
removed, showing the burrows of Polygraphus rufipennis. 
Note the engravings with one, two and four egg-galleries. 
It will be seen that the egg-galleries are typically and nearly 
invariably transverse, while the larval mines are longitu- 
dinal. Reduced to seven-tenths natural size. 

Fig. 3. Burrows of P. rujipennis in the inner bark of 
the trunk of the American larch. ISTote the direction of the 
egg-galleries and the variation in the number of these in the 
different engravings. The bark even on the trunk of larch 
is relatively thin, and therefore the nuptial chamber is here 
at the juncture of inner bark and sapwood. Slightly less 
than one-half natural size. 

Fig. 4. Burrows of P. rufipennis in the inner bark of red 
spruce. The bark here is thicker than in larch and the 
nuptial chambers of the burrows are therefore in the outer 
part of the inner bark and not visible. Reduced to about 
three-fourths natural size. 

Fig. 5. Section of the trunk of larch from which the 
greater part of the outer bark has been removed by wood- 
peckers, exposing numerous burrows of P. rufipennis and 
one burrow of Monohammus scutellatus. These birds have 
acted as a partial check upon the borers, as a large per cent 
of the latter had been eaten by them; yet in spite of their 
work the number of borers which remained alive was con- 
siderably larger than the number originally entering the 
bark. Thus, while woodpeckers render efficient assistance in 
keeping down the numbers of boring insects, they cannot be 
depended upon to restore the balance of nature unless aided 
by artificial or by other natural factors. Reduced to about 
two-fifths natural size. 



Plate II. 







Plate III. 

Fig. 6. Another section of trunk of larch tree showing 
the work of woodpeckers in removing the outer bark in order 
to feed upon the borers therein. In this case the work has 
not been quite so thorough as in Fig. 5. Reduced to about 
two-fifths natural size. 

Fig. Y. General view of the engravings of Eccoptogaster 
picece upon the surface of the wood of larch tops, showing 
the general appearance of larch wood one year after it has 
been attacked. This section of the tree contained nearly a 
pure culture of E. picece, but one engraving of P. riifipennis 
may be seen near the lower left-hand corner of the photo- 
graph. IsTote the different types of burrows. Reduced to 
slightly less than two-fifths natural size. 

Fig. 8. Engraving of E, picece in larch, showing the bur- 
row with two egg-galleries, which is the most common type. 
Note that there is a much larger number of egg niches in 
the upper egg-gallery, although in this case the two are about 
the same length. Typically the upper egg-gallery, which is 
the first one begun, is both longer and contains more egg 
niches. The larval mines at first are nearly parallel to each 
other and at nearly right angles to the egg-gallery, but later 
they become very tortuous. The wider, deeper, more tortuous 
burrows (as those in the upper left-hand region of the pic- 
ture), which appear whiter on account of their grooving the 
sapwood so deeply, are made by the young adults, which feed 
in the old host for a time before emerging. About four-fifths 
natural size. 

Fig. 9. Engraving of E. picece with three egg-galleries. 
About four-fifths natural size. 



Plate III. 













Plate IV. 

Fig. 10. Burrow of Eccoptogaster picece in larch, having 
only one egg-gallery. The length of this one is remarkable 
even for uniramous burrows, as is also the number of egg- 
niches. Slightly more than three-fourths natural size. 

Fig. 11. View of the inner bark of larch, showing the 
burrows of Crypturgus pusillus arising from the engravings 
of P. nifipennis. This shows the usual confused appearance 
after the larvae have developed and destroyed the egg- 
galleries. The flocculent white material is due to fungi. 
Reduced to about four-fifths natural size. 

Fig. 12. Engraving of Crypturgus pusillus in the inner 
bark of red spruce. In this case twenty-two egg-galleries 
arise from the nuptial chamber of an abandoned burrow of 
P. rufipennis and several more from the egg-gallery. The 
egg-galleries here are not so much destroyed by the larvae 
as usual because most of these have burrowed at another level, 
in the outer part of the inner bark. About three-fourths 
natural size. 

Fig. 13. Engraving of C. pusillus in inner bark of larch. 
Here also the egg-galleries originate from the nuptial cham- 
ber of P. rufipennis. About four-fifths natural size. 



Plate IV. 





Plate V. 

Fig. 14. Segment of the trunk of larch with bark removed, 
showing the burrows of Polygraphus rufipennis and Phyma- 
todes dimidiatus. The wider grooves in the wood, many of 
which end in oval openings leading down into pupation 
chambers, are made by P. dimidiatus. About two-thirds 
natural size. 



Plate V. 




Plate VI. 

Fig. 15. Burrows of Phymatodes dimidiatus in trunk of 
larch. ISTear the center can be seen the complete larval bur- 
row, the entrance to the pupation chamber and the exit hole. 
The entire burrow is relatively short, as would be expected 
of a one-year form. Reduced to about two-thirds natural 
size. 

Fig. 16. Burrow made by the larva of Monohammus 
scutellatus in white pine. All of the larval work cannot be 
seen, but characteristic points are shown. !Note that the 
part of the burrow adjacent to the chamber in the wood used 
for retiring, hibernation and pupation has been kept free of 
frass, while much of the rest is packed full of the character- 
istic " sawdust " like detritus. Note also the oval opening 
leading to the pupation chamber (below) and the nearly 
exactly circular exit opening (above). Reduced to slightly 
less than one-half natural size. 

Fig. 17. Thin-barked limb of white pine showing where 
the adults of M. scutellatus have fed upon the thin smooth 
bark. At various places in the smoother areas of the bark 
can be seen the work of the mandibles of the beetles. The 
females oviposit in such areas and the several small white 
spots in these areas indicate " ventilation openings " through 
which the newly hatched larvse have extruded the white frass. 
These " ventilation openings " of the very young larvae are 
the openings made by the ovipositor of the female, which 
have been enlarged and utilized by the newly hatched larva. 
Reduced to about one-half natural size. 

Fig. 18. Portion of the trunk of a small larch sapling, 
showing the burrow of Leptostylus sex-guttatus. The entire 
burrow, including larval mine, entrance to pupation chamber 
and exit hole, is shown. This being a two-year form, the 
burrow is relatively quite long. Slightly more than one-half 
natural size. 



Plate VI. 





/r 




/6 



Plate VII. 

Fig. 19. Burrow of Neoclytus longipes in limb of larch. 
This cerambycid is a two-year form and the larval burrow 
liere is narrow, deep and extraordinarily long. After groov- 
ing the sapwood just beneath the bark for most of its life, 
the larva bores through the sapwood for some distance before 
pupating. Thus the exit hole may be on the opposite side 
of the limb from the point of entrance to the chamber in the 
wood. Slightly more than one-half natural size. 

Fig. 20. Another burrow of N. longipes in a larch limb. 
This burrow is perhaps more typical from the fact that the 
larva tunneled the wood for a distance of 10^ cm. before it 
pupated. Reduced to slightly less than one-half natural size. 

Fig. 21. Burrows of Pogonocherus inixtus in larch. The 
burrow is here rather short but quite wide for so small a 
form. Entrance to and exit from the pupal chamber is 
through the same opening. This is not so common among 
cerambycids as it is with the buprestids. About one-half 
natural size. 

Fig. 22, Burrow of Anthaxia quercata in limb of larch. 
The burrow made by this small flat-headed borer during its 
first year is shallow and rather narrow, but during the second 
year the larva is likely to excavate a broad area rather than 
continue it as a linear mine. The adult emerges from the 
pupal chamber through the same opening by which the larva 
•entered. x\bout ftve-eighths natural size. 



Plate VII. 




/3 




£0 





^^ 



Plate VIII. 

Fios. 23, 24. Burrows of Chrysobothris hlanchardi in 
larch limb. The larval mine during the first year is likely 
to be linear and is usually not very tortuous while that made 
during the second year is very tortuous. The adult in emerg- 
ing from the pupal chamber uses the entrance burrow made 
by the larva. The two burrows shown in Fig. 24 are quite 
typical. Fig. 23 reduced to about one-half natural size. 
Fig. 24 reduced to about two-fifths natural size. 

Fig. 25. Burrow of C. hlanchardi in larch from which 
the frass has not been removed. !N^ote that this material 
forms alternate bands of light and dark. This is produced 
by the habit of the larva in excavating from the bark and 
from the sap wood alternately. This material is arranged to 
form curved striae by the abdomen of the flat-headed larva, 
which is habitually bent to form a loop and pressed against 
the frass in order that the borer may obtain leverage in rasp- 
ing off the fibres. Reduced to about two-fifths natural size. 

Fig. 26. Burrow of Chrysobothris sex-signata in small 
larch sapling. The burrow here is relatively shallower and 
wider than those made by the foregoing buprestids. That 
made during the second year is especially wide. The larval 
entrance to the pupal chamber is used by the adult in emerg- 
inc;. Reduced to about five-ninths natural size. 



Plate VIII. 




a^ 



Z4 




£Si 




Plate IX. 

Fig. 27. Burrows of Chrysohothris dentipes in white 
pine. The greater part of the hirval burrow of this species 
is in the sapwood immediately under the bark. When nearly 
full grown the larva tunnels into the wood and often bores 
through this for a distance of several inches before pupating. 
In emerging the adult makes an opening of its own which is 
often at some distance from the point at which the larva 
entered the wood. Reduced to slightly less than three-fifths 
natural size. 

Fig. 28. Section of the trunk of larch showing the burrows 
of Polygraphus rufipennis (upper left) and of Eccoptogaster 
picew (right) and the exit holes of Urocerus alhicornis. 
Reduced to about two-thirds natural size. 

Fig. 29. View of a segment of the trunk of Tree V. The 
exposed decaying wood was killed a number of years ago, 
probably by peeling. At that time it had been tunneled by 
the larvse of Serropalpus harhatus and perhaps other forms, 
and decay had for this reason been more rapid. A specimen 
of Adelocera hrevicornis was taken from this wood in the 
field, and Tenehrio tenehriodes and Dryophthorus ameri- 
canus were bred from it in the breeding cages. The more 
recently killed wood at the sides shows the engravings of 
P. iiifipennis. Reduced to one-third natural size. 

Fig. 30. Portion of the heart wood from Tree V, showing 
the larval burrows made by Serropalpus harhatus many years 
before. The burrows of Dryoplitliorus americanus may be 
seen at various places. This insect bores in the soft " spring 
wood," leaving the harder " summer wood " nearly intact. 
Reduced to about two-thirds natural size. 



Plate IX. 




t«3 ^' 






30. 



